We're No. 1 (and We're Going to Stay That Way)

Why the prophets of American decline are wrong.

"The United States cannot afford another decline like that which has characterized the past decade and a half.... [O]nly self-delusion can keep us from admitting our decline to ourselves." 

-Henry Kissinger, 1961

For all our optimism, Americans have always worried about our place in the world. It's in our DNA, and it helps drive our renewal. To borrow from the great political scientist Samuel Huntington, "[T]he United States is unlikely to decline so long as its public is periodically convinced that it is about to decline. The declinists play an indispensable role in preventing what they are predicting."

When Kissinger wrote the above words in 1961, he did have some valid concerns. At the time, the U.S. economy was struggling to grow its way out of a recession. The Soviet Union had launched the world's first artificial satellite, known as Sputnik, into orbit. The nation went into a panic, thinking we had fallen behind in technological innovation and would soon be outspent and outmatched by Moscow.

And yet the decade and a half that was the subject of Kissinger's fears -- the period from the end of World War II until John F. Kennedy's administration -- is now seen by most historians as an era of unparalleled American economic growth and power. The decade that followed was even more prosperous, ending with the United States, not the Soviet Union, making the first lunar landing. And a mere 30 years after Kissinger wrote those words, the Soviet Union had ceased to exist entirely.

Every 10 years or so, a new bout of profound pessimism has swept the nation. In his fine book, The Myth of America's Decline, the German journalist and author Josef Joffe documents these periodic waves of declinism.

Declinists in the late 1960s asserted that the cost of the Vietnam War and social and racial tensions would bring about what one prominent historian called "the unraveling of America."

In the 1970s, declinists signaled the end by pointing to inflation, oil shocks, and unemployment. An ally fell in Iran and the Soviets invaded Afghanistan. In the 1980s, Americans looked with awe and fear at Japan's growing economic strength, and historians said we would soon become one of history's forgotten empires. But in each instance, the sky didn't fall, the United States didn't sink into the ocean, and it remains the most preeminent nation on Earth.

We need to be humble about our ability to predict the future with certainty, but the evidence is that there has long been a tendency to underestimate America's staying power.

Today, the declinists are back, arguing that China will soon overtake us and that our gridlocked politics, long-term deficits, and decaying infrastructure will prevent us from playing the same global role that we have since World War II.

We must take these concerns seriously and not assume that America will retain its primacy simply because declinists in the past have turned out to be wrong. Leadership is not something the United States has by happenstance -- it is something we have had to earn over and over again.

So how do we actually quantify power? Former National Security Advisor Zbigniew Brzezinski, in his latest book, Strategic Vision, assigned the United States a strategic balance sheet of assets and liabilities. His framework sets up a useful way of analyzing where we stand today. We certainly have strategic liabilities that we cannot ignore. But what is sometimes lost in the periodic wringing of hands is just how extraordinary and enduring America's assets are -- first and foremost our ability to deal with whatever challenges may come our way.

Measuring power in today's globalized world is a complex task. A country's strength and influence go beyond the old, one-dimensional quantifiers that we used to use, like steel outputs and troop numbers. While our military might is tremendous and essential, power today is more often exercised through economic vitality, the capacity for innovation, a vibrant and stable political system, and a resilient society.

It is not measuring strength in one or two dimensions that captures a country's position, but rather the accumulation and the interaction between these assets. Here, then, are five of those core strengths:

Economic resiliency

More than anything else, the American economy is the wellspring of our global leadership. There are not a lot of iron laws of history, but one of them is that a nation's power is directly related to its economic strength. As President Barack Obama has said, "Our prosperity provides a foundation for our power."

The 2008 financial crisis tested our resilience and dealt a real blow to our international prestige and authority. Long-term challenges remain. But the fact is that no country comes close to matching our fundamental economic strength. The U.S. economy is built on a sound structural foundation, combining an entrepreneurial orientation, deep and efficient capital markets, highly experienced managers, and strong technological leadership.

By every measure, the United States has the largest national economy in the world today, generating nearly $17 trillion in GDP. Our economy is nearly double the size of the second-largest, China's. Our stock market capitalization is five times bigger than China's. We lead the world in attracting foreign direct investment and are also the world's largest single investing economy.

An economy's most important asset, however, is not its sheer size. China's enormous population base will put it on a path to become the largest economy in the world at some point in the future. But history shows that size alone has not been the most important factor in determining the most powerful nation. At the peak of Britain's global power, it was China that had the world's largest economy, even though the country was then a middling power in the throes of what the Chinese refer to as their "century of humiliation."

A far better measure of an economy's health is its quality and sustainability. We have the wealthiest large economy in the world, as well as one of the most diversified and technologically advanced. China has a very large economy, but it's still a poor country. According to the World Bank, U.S. GDP per capita is $53,143; China's is $6,807. That provides an important perspective.

And when we look to our prospects for the future, it's clear that the United States is well poised to maintain our leading position. Think about three aspects of our economy: innovation, energy, and higher education.

First, the United States has an innovation edge over the rest of the world. Apple, Google, Facebook, Twitter -- all are synonymous with American economic vitality today, but only one of these companies existed 15 years ago. The eight largest technology companies in the world by market capitalization are based in the United States. And when it comes to the next frontiers in extraordinary breakout technology, like 3-D manufacturing, artificial intelligence, nanotechnology, cloud computing, robotics, big data, and advanced material science, American entrepreneurs and companies are leading the way.

The United States also leads the world in research and development, with a projected $465 billion in spending this year -- that's over 30 percent of all global R&D.

Like so many of our strengths, our innovation advantage didn't happen by accident. It stems from the combination of a risk-taking culture, significant investment by the American government in research, the best universities in the world churning out good ideas, and the kind of regulations and access to liquid and deep capital markets that make it possible to turn those ideas into businesses. And all these strengths come together in Silicon Valley, which represents to the world our spirit of creativity and innovation.

A second -- and frankly unexpected -- U.S. economic asset is our national energy outlook.

For most of the past 40 years, the United States thought of itself as a nation dependent on oil and energy-related events beyond our shores. Now, as U.S. innovation and technology allow us to tap unconventional resources, nearly every prediction about our energy future has been turned on its head.

Today, the United States is the No. 1 producer of natural gas in the world, and the price of natural gas here is a fraction of what it is elsewhere. The International Energy Agency projects that the United States will be the world's largest producer of oil by the end of the decade. Unconventional energy will propel our economy and support American jobs -- nearly 900,000 by next year will come just from shale gas. 

Meanwhile, our new energy security is allowing us to engage the world from a position of strength. It gives us the latitude to support allies and, if need be, punish adversaries. The success of the international sanctions on Iran, for example, was made possible in large part because Washington was confident that increased American supply afforded it the possibility of removing a million barrels of Iranian oil off the market each day without dramatic increases in gasoline costs to U.S. consumers. And it was the bite of those sanctions that ultimately brought the Iranians to the negotiating table last year. 

Like our success in innovation, this energy renaissance did not happen by accident or because of luck -- it is truly an only-in-America story. Many other countries have promising shale deposits. The reason that the United States has seen such dramatic and fast-paced energy changes is because decades ago, we made wise, significant investments in key technologies, and we have the right balance of an open investment climate, an innovative and entrepreneurial spirit, environmental safeguards, infrastructure, and property ownership rights. Today, the wide availability of cheap natural gas in the United States has become a major competitive advantage for our energy-intensive manufacturers, particularly compared with Europe and China.

Meanwhile, the reduction of energy imports has brought our trade deficit to a four-year low, which allows a greater share of the money Americans spend on energy to remain within the country. We also now have the opportunity for the export of both natural gas and crude oil to the world, which will support our allies, stabilize the world's energy supply, and expand our own prosperity.

Another source of long-term economic strength is America's higher education system. Our universities are the envy of the world. We are home to 17 of the top 20 research universities. Our scientists publish far more papers in prominent journals than those in any other country. In 2013, a record 820,000 foreign students were enrolled at U.S. universities. 

Warren Buffett summed it up nicely in his latest letter to his shareholders: "I have always considered a 'bet' on ever-rising U.S. prosperity to be very close to a sure thing. Indeed, who has ever benefited during the past 237 years by betting against America? If you compare our country's present condition to that existing in 1776, you have to rub your eyes in wonder. And the dynamism embedded in our market economy will continue to work its magic. America's best days lie ahead."

Military might and alliances

By any measure, our military power is unmatched, and that's not likely to change anytime soon. In terms of sheer size, the United States spends more each year on defense than the next 10 nations put together. Our defense budget is more than five times bigger than that of our nearest competitor, China -- despite that country's rapid military buildup. Even after 13 years of war -- the longest period of continuous conflict our armed forces have ever seen -- we remain capable of defeating any adversary.

But even these measurements underestimate our military's true advantages. The U.S. Navy owns 11 of the world's 20 aircraft carriers, making America the only country on Earth with a truly global power projection. With more than a decade of experience fighting terrorism, our special operations forces have become a unique American asset. The May 2011 raid on Osama bin Laden's compound in Abbottabad, Pakistan -- over 7,000 miles away from the United States -- was only the most visible example of how our battle-tested special operators successfully execute complex missions in dangerous places across the globe. 

And by historical measures, the current U.S. defense burden is not excessive as a share of GDP. As we wind down the war in Afghanistan, our military now stands on a more sustainable footing, without the kind of overstretch that some have worried about.

We also possess a network of formal alliances with over 50 nations -- the largest in history. Centered on our treaty alliances in Asia and Europe, this network has been built for over half a century on a bipartisan basis. No other country can look to anything like it. These enduring partnerships are a unique American strength, and we continue to deepen them across the globe today.

The luck of geography

Geography and natural resources are our most natural advantage. These enduring strengths are rarely discussed, but they have provided for the safety and prosperity of the American people from the days since the first settlers arrived. We are an Atlantic and a Pacific power, an American and an Arctic nation. We are protected by oceans and peaceful borders. We live in a hemisphere of mostly stable democracies, and we enjoy friendly, productive relations with our fellow American states. The bottom-line strategic point is that the United States does not face any real threats in its own hemisphere.

Almost uniquely, the United States is not a dependent power. In addition to our energy resources, we have other diverse and valuable sets of natural resources. The United States has the largest deposits of rare-earth minerals at a time when competition for those resources is on the rise. Our country is situated on the largest fertile land mass, helping make us the breadbasket of the world. We are the largest food exporter, and our rich farmlands help insulate Americans against price shocks and food shortages. None of this means that the United States can afford to ignore what takes place beyond our shores -- our interests are too great and the fate of nations is too interconnected -- but it provides us greater latitude to pursue our interests across the globe.

Demography and immigration

We are likewise blessed to have a bright demographic future. Our workforce is relatively young and still growing. Between now and 2050, the U.S. population is expected to grow by nearly 100 million people, expanding our workforce by 40 percent. Contrast that with the populations of other developed nations in Western Europe, Japan, and South Korea, which are aging and shrinking. By 2050, the median age in China will be nearly 50; in the United States it will be 40. 

A big part of the reason our demographic profile looks better than the rest of the world's is that we are a nation of immigrants. Immigrants are both younger than the population at large and participate in the workforce in larger numbers than those born in the United States. Immigrant communities are also a tremendous source of creativity, and the United States has a distinct advantage over other developed nations when it comes to attracting highly skilled immigrants. Foreign entrepreneurs and scientists choose to make the United States their home because it is easier to enter our labor markets and move within them than in any other developed country. Our open society allows for more seamless integration than anywhere else.

That's why it's so important for Congress to pass a comprehensive immigration reform bill. Reform is not just a domestic issue -- it's a strategic issue -- and it's crucial to locking in our global advantage in human capital.

The virtues of leadership

The final asset is America's unique global leadership role. For generations, Americans have taken up the mantle of leadership in a world torn by war and scarred by oppression. We have repeatedly put American blood and treasure on the line to defend our values and advance universal rights. The world still expects us to lead today. People everywhere look to America to protect global commerce, ensure the free flow of energy, and control the spread of dangerous weapons.

Plenty of countries have leverage. But there is a very big difference between leverage and leadership. The United States brings to bear more than just resources. It has an unmatched ability to convene countries and coordinate international efforts. That's because of the attractiveness of our ideas, our tradition of leadership, and the fact that we've nurtured such a successful international system.

Former Secretary of State Madeleine Albright calls America the "indispensable nation"; that's because few global problems could be solved without American involvement. Our allies in Europe, the Middle East, and Asia clamor for active U.S. engagement in their regions. Although American power is occasionally resented, there is broadly a strong attraction to our values of democracy, free markets, and respect for human rights. A principal dynamic in the world today is not a rejection of American leadership but rather a demand for more of it. It is impossible to imagine any other country assuming the global leadership role we currently play.

Challenges and headwinds

For all the tangible and intangible virtues of American primacy, we must also be clear-eyed about the liabilities side of our strategic balance sheet. Here are five big concerns.

Getting control of the U.S. long-term budget deficit is critical. America's fiscal position risks undermining its overall economic foundation. Despite the general impression to the contrary, the fact is that in the last several years our deficit has dropped precipitously -- in fact, faster than in any period since the demobilization after World War II. But in just two years, deficits will begin rising again, driven mainly by mandatory entitlement spending. As a result, we will have less flexibility to make useful investments in the future of our country, from science and technology to the national defense.

In taking on our deficits, economic growth should continue to be our priority in both the short term and the long term. Former Treasury Secretary Larry Summers has estimated that an increase of just one-fifth of 1 percent in annual economic growth would address the projected long-term budget gap. 

Second, our infrastructure is falling into disrepair. Just five years ago, the World Economic Forum ranked our infrastructure ninth best in the world -- today it's 19th, and U.S. public construction spending as a percentage of GDP has plummeted to its lowest point in 20 years. Our overburdened roads and bridges create a situation that is environmentally, politically, and economically unsustainable.

The United States has a long history of investing in infrastructure to support economic expansion and growth. The current combination of absolute need, persistent post-crisis unemployment, and favorable borrowing rates for the government make this a uniquely favorable time for a major infrastructure effort. Indeed, it is hard to imagine a better time.

Third, we can no longer take our advantages in innovation for granted. China and Japan have already surpassed us in the number of patents filed each year, and China is quickly catching up in terms of R&D spending. That's why it's such an important national priority that our government continue to invest in advancing scientific knowledge.

At the same time, our failure to overhaul our immigration system is blunting our natural edge in the global competition for talent. Forty percent of the people receiving advanced degrees in science, technology, engineering, and mathematics at American universities are foreign nationals with no legal way to stay here, even if they would choose to do so. American business leaders regularly express frustration that our current immigration laws make it hard for them to hire talented individuals from abroad, limiting their ability to grow their companies. And our competitors are already changing their policies in order to attract the best and the brightest from around the world. That is a cause for national concern. Passing common-sense reform would allow us to meet the needs of the 21st-century American economy.

Similarly, we need a wake-up call when it comes to primary and secondary education. Our universities are the best in the world, but we rank 14th on Pearson's well-regarded education index for grade school. This is simply unacceptable. If we are going to prepare Americans for the jobs of the future and restore middle-class security, we have to out-educate the world. That starts with a strong school system that stretches from pre-K through college.

Overcoming these liabilities will take time and difficult choices. But here's the key point: None of these challenges is insurmountable. Every one of them has a policy solution in sight that is feasible and affordable for our nation. Addressing them in each case is a matter of mustering the political will, as we've done for the last 200 years.

With the worst of the economic crisis behind us, and as we move off of a permanent war footing, now is the time for smart choices and wise investments that will sustain American power and leadership for generations to come. We must continue to build on our assets and squarely take on our liabilities. That means taking all the necessary steps to enhance economic growth, including passing comprehensive immigration reform, ramping up our investment in science and technology, repairing our infrastructure, and undertaking more thoroughgoing political reforms to restore the health of our democracy. This is a common-sense agenda that should have bipartisan support.

As we continue to renew our nation, our fundamental strengths will propel us forward. Our open society and democratic institutions set us apart. Our military remains the strongest in the world, and we will continue to lead on the international stage. Our institutions will allow us to pursue the kind of just and sustainable growth that our changing society needs. We are younger than our competitors, and our economy will continue to be more vibrant.

I was recently reminded of a conversation I had with Henry Kissinger during my time in the White House. I asked him what he made of all this renewed talk of American decline. And I'll never forget his reply. He said "Well, Tom, would you rather be national security advisor for any other country?" The answer was self-evident -- of course not.

Dan Kitwood/Getty Images


The Build-It-Yourself Bombs

Cheap, deadly, and not stopping anytime soon, barrel bombs are the weapon of choice for dictators from Sudan to Syria.

The camera wobbles and the image pixelates as the cameraman tilts upward to catch the Syrian military helicopter drop its payload. The video, which has been viewed more than 76,000 times, follows the barrel bombs' tumbling descent, the roar of their fall growing louder. The bombs hit their targets in a closely-packed urban area with an enormous crash, sending a huge plume of dark gray and white smoke, dust, and debris rising up as the building gives way. The video, reportedly from the Damascus suburb of Daraya, was uploaded by anti-government media activists from Syria in February. The accompanying video description refers to the weapons as barrel bombs -- and ordnance tumbling from a Russian Hip helicopter, with visible fins, is likely just that. Similar to many of the videos available online of these bombings, the precise details of the attack in question, like the number of dead and wounded, are not known.

The Syrian air force's indiscriminate use of barrel bombs against rebel-held targets across the country have caused widespread terror and helped fuel Syria's growing humanitarian crisis. At least 240,000 Syrians are living under siege, and, as recently reported in Foreign Policy, barrel bombings are playing their part in preventing food shipments and medical supplies from reaching the neediest civilian populations of the war-battered countries. United Nations Secretary General Ban Ki-moon recently told the U.N. Security Council that Syria has seen "an intensified use of barrel bombs by government forces against civilian populations," with the attacks inflicting heavy damage to infrastructure and causing large number of civilian casualties.

Videos of these bomb drops and soot clouds populate YouTube -- sometimes in disturbing mega-compilations. The videos from Syria are most often shot and disseminated by Syrian citizens documenting attacks on them, although one appears to have been shot from inside a Syrian military helicopter. Many mirror the one described above, training the camera first on the helicopter, then on the falling bomb, and then zooming in on the gray, brown and white soot cloud of another destroyed building and another group of dead Syrian civilians, their exact numbers unknown and unknowable.

Most Americans didn't know barrel bombs existed until news of their widespread use in Syria began to emerge from the shattered country earlier this year. But the weapon -- cheap and easy to manufacture -- has long been used in both Iraq and Sudan as well. In Iraq, where the government has used barrel bombs against Sunni insurgent groups, including the Islamic State of Iraq and al-Sham, citizen journalists and media collaboratives have filmed and uploaded a handful of videos showing not the explosions themselves, but the remains of the weapons -- dusty plates and barrels in craters and rubble -- as evidence of the use of barrel bombs. The bombs haven't just been used in the Middle East. In Sudan, government forces have used them against rebels and civilians in Darfur, South Kordofan and Blue Nile, causing widespread carnage. In contrast to the vast array of online footage from Syria, and even the few recent uploads from Iraq, no videos whatsoever seem to be available from the Sudan bombings.

The sheer number of videos is a godsend for scholars of the Syrian war, like Richard Lloyd, to pore over.* Lloyd has contributed to the detailed information made available by British investigative blogger Eliot Higgins, whose Brown Moses blog has become a trove of data on the Syrian conflict, including barrel-bomb technology. A 53-year-old from Spokane, Washington, Lloyd is a warhead technology expert at Tesla Laboratories and has spent the past year watching these videos and analyzing them for an understanding of the design and construction of Syria's barrel bombs. Over the phone, he explains the time he spends trying to understand the way the weapon -- increasingly a mainstay of Syrian strongman Bashar al-Assad's war against his own people -- has evolved. As a result of the amount of evidence available and Lloyd's interpretation of it, a great deal more is known about the evolution of the barrel bombs and the impact of their use than had been available from the weapons' earlier deployments in Iraq and Sudan. "I search all the videos every day," he says. "I watch the barrel bomb drop and analyze that. Analyze the helicopter. Watch it hit the ground. See if there's an explosion."

From footage of a bomb's aftermath, he analyzes the exploded ordnance for its design, its diameter, and the type of explosive used. When he watches footage of an explosion itself, Lloyd scrutinizes it to figure out the blast radius and estimate the damage, using the height of the soot cloud to determine the amount of explosive material in the bomb. Over the course of his analysis, he has managed to illustrate something of a timeline of Syria's technological development of barrel bombs and to note some of the most important shifts in their design, ones that have affected their destructive force. The design shifts he has been able to observe range from a dramatic size increase to changes in the fuses and external attempts to keep the barrel bombs from tumbling around while they descend-- evidence of the Syrian army's investment in the use of these munitions.

Barrel bombs are about as far from a precision weapon as you can find. A U.S. drone can fire a missile into a moving car from tens of thousands of feet away; a barrel bomb is a crude device that is basically just tossed out of a helicopter or plane without any regard for where it lands. However hit-or-miss they may be, though, barrel bombs are an easily constructed way of creating fear. They're typically built from oil drums, scrap metal, or rebar, and explosives, and they can cost as little as $200 to $300, Lloyd estimates. You get what you pay for: The bombs are often duds that fail to explode on impact or that destroy themselves in midair explosions. When they do hit, however, these bombs have the capacity to inflict extraordinary harm and steep casualties. In an especially bloody nine-day barrel-bomb offensive on the northern Syrian city of Aleppo in December 2013, barrel bombs are thought to have killed more than 300 people, 87 of them children. In one attack on the Masaken Hanano market, an activist reported to Al Jazeera that medics were "removing people in parts."

In many ways, barrel bombs are a kind of airborne version of the improvised explosive devices (IEDs) that were used to devastating effect in Iraq and Afghanistan. IEDs in the two war zones often functioned like land mines, with insurgents burying raw explosive or artillery shells underground and using garage-door openers or cell phones to detonate them when U.S. troops or vehicles passed by. The bombs were the leading killers of U.S. troops in both countries, leaving more than 3,000 dead while wounding more than 33,000 more. Do-it-yourself weapons like IEDs are a hallmark of insurgency and rebellion, of desperation and limited resources. Barrel bombs can be used by insurgents, but they are usually dropped from helicopters and aircraft belonging to state militaries. Either way, they serve the same purpose as a traditional IED: killing and wounding enemies cheaply and easily.

They're also becoming increasingly popular. Barrel bombs have been in the news lately because of Syria, but an earlier incarnation was first seen on the battlefields of Iraq in 2007. This older version of the weapon consisted of "lob bombs," which functioned as crude mortars for the insurgents battling U.S. forces in the later years of the Iraq war. A predecessor of sorts to the barrel bombs seen in Syria and Sudan, they were built the same way: Emptied-out propane tanks were packed with explosives, scrap metal, and ball bearings. Rather than dropped from the sky, they were launched in an arc trajectory from ground level, usually from truck beds. Ordnance of the current heft and design of a barrel bomb requires helicopters, and helicopters virtually always mean a state army.

That was the case in Sudan in 2011, when government forces rolled barrel bombs and other unguided munitions out of the backs of Russian-made Antonov cargo planes against rebel and civilian targets in the South Kordofan and Blue Nile regions. The barrel bombs were among the bombs used in Sudanese forces' indiscriminate aerial bombardments when conflict broke out in 2011 with the southern rebel group the Sudan People's Liberation Army. One woman told Human Rights Watch investigators about the impact of a barrel bomb hitting her and a group of 25 other civilians as they made their way toward South Sudan in late 2011, saying "When [the bomb] hit, there was just smoke and dust and I couldn't see anything. Moments later I saw my daughter and I called to her to see if she was injured. And then I saw the blood of my daughter. Within minutes the Antonov dropped a second bomb." These bombs were similarly used by Khartoum over the past decade in its campaign in Darfur, according to eyewitness accounts that were given to Amnesty International. Smith College professor Eric Reeves reported in 2012 that the Sudanese bombs "explode not with a large blast capability (and often do not explode at all), but have enough force to generate a hail of deadly shrapnel in all directions." He added, "They are not by nature a military weapon, but a tool for civilian destruction and terror." Sudan appears to have continued using the weapon. A recent Amnesty International report found that barrel bombs were among the ordnance dropped on South Kordofan in May.

Sudan has made wide use of barrel bombs, as has the Syrian government, and they have begun to return to Iraq as well. In May, an Iraqi army desperate to beat back insurgents from the Islamic State of Iraq and al-Sham (ISIS, and recently renamed the Islamic State) dropped the bombs on ISIS targets in the rebel-controlled city of Fallujah. Residents there described helicopters dropping barrel bombs on residential neighborhoods, coming across unexploded barrel bombs, and the sounds of large explosions and the wide areas of destruction that Human Rights Watch calls consistent with barrel-bomb attacks. An anonymous official in Anbar province confirmed the use of barrel bombs to Reuters, calling the bombings a "scorched-earth policy -- the destruction of a whole area." The official said the Iraqi Army was using the barrel bombs because it lacked experience "in house-to-house fighting, which the rebels have mastered. That's why they've resorted to this."

Syria, though, is where barrel bombs are increasingly a government's weapon of choice, with catastrophic results for the rebels on the ground and the civilians caught in the crossfire. The insurgents' acquisition of anti-aircraft weaponry has forced Assad's helicopters to fly higher, which means the bombs are even less precise once they make their long way down to the ground. Assad's growing use of the weapon, which has been confirmed and condemned by the United Nations, has helped Syrian engineers sharply increase the bombs' power. In the early stages of their use, barrel bombs weighed between 100 and 300 pounds. Now their weight has multiplied; individual bombs range from 1,000 pounds to a full ton.

The lighter-weight bombs had been ignited with simple fuse wicks lit with cigars and had been pushed from Russian Hip helicopters. As the bombs changed in size, they evolved, with wicks giving way to impact fuses designed to explode on contact when they hit the ground. Barrel bombs have also been given crude fins to prevent them from tumbling around while they descend and to increase the likelihood that the bombs will land on the impact fuse. They have also been adapted to be carried by Russian Hind helicopters, which formerly could only transport and drop conventional bombs.

Packing chlorine-gas canisters inside the barrel bombs is another deadly addition. In May, Human Rights Watch said that there was strong evidence that Syrian government helicopters dropped the weapons on three towns in northern Syria in mid-April. Local doctors told the human rights group that the attacks killed at least 11 people and left 500 more with symptoms consistent with exposure to the toxic substance. Although it does not have the lethality of sarin, chlorine gas can still inflict harm, particularly on a population weakened by siege and already terrified by the prospect of chemical weapons. "Syria's apparent use of chlorine gas as a weapon -- not to mention targeting of civilians -- is a plain violation of international law," Nadim Houry, the deputy Middle East and North Africa director at Human Rights Watch, said in a statement at the time. "This is one more reason for the U.N. Security Council to refer the situation in Syria to the International Criminal Court."

Barrel bombs are far from a perfect weapon, but however hit-or-miss they may be, they are a cheap way of creating fear. They often miss their targets, and design flaws lead to duds and midair explosions. When they do hit, however, these bombs have the capacity to inflict extraordinary harm and steep casualties. In some ways, however new these weapons may seem, they are a very old-school piece of technology: inelegant, blunt-force combinations of metal and high explosives, deployed with a heavy hand. Barrel bombs stand out in contrast with modern warfare's vast array of skillfully engineered smart bombs and guided weaponry, all designed with precision in mind. Nevertheless, their continued use seems as much a part of future conflicts as the sleeker, higher-tech ordnance. Turns out that the future of the war may come from its past.

Correction, July 7, 2014: Richard Lloyd is an expert on weapons technology. An earlier version of this article incorrectly described him as an amateur scholar. (Return to reading.)