It remains to be seen whether Morsy's supporters can prove as skilled as those of Iran's revolutionary leader Ayatollah Khomeini at exploiting the deaths of "revolutionary martyrs." There's no question that the Brotherhood is well-organized, but, as Morsy's stint in office demonstrated, they're also shockingly oblivious to political dynamics outside of their own movement. And while Morsy certainly commands the support of a considerable bloc of sympathizers, their political weight is probably equaled or neutralized by that of the Egyptian armed forces.
In the past, even opposition movements that have overwhelming majorities behind them have found it hard to bounce back from attacks by ruthless governments. The 1960 Sharpeville massacre in South Africa, when police killed 69 demonstrators, undercut the legitimacy of the white-minority regime, dramatically deepened South Africa's international isolation, and prompted the opposition movement to found its first armed guerrilla organizations. Even so, non-white South Africans had to wait another 34 years until apartheid finally gave way.
That was in a country where the rulers accounted for less than 10 percent of the population. But what about British-ruled India? In 1919, a unit of the British Indian army opened fire on unarmed protestors in a public garden in the city of Amritsar, killing up to 1,000 people -- including many women and children. (This was at a time when a little more than 100,000 Britons on the subcontinent were lording it over a population of 250 million.) The news of the Jallianwal Bagh massacre prompted a surge of anger around the Raj, giving a big boost to the Indian nationalist movement. Yet there was no nationwide uprising. British guns and organization, combined with a deeply fragmented Indian opposition, enabled London to maintain its grip until 1947.
The use of indiscriminate, overwhelming force against protestors (even angry, violent ones) is always reprehensible. From a purely Machiavellian standpoint, though, there are few more effective ways to cow your opponents -- especially if you're a government firmly in power and they're a scattered bunch of unarmed dissidents. Just ask the members of Burma's former military junta, who managed to keep themselves on top for 50 years by repeatedly demonstrating their willingness to use deadly force against demonstrators. The leaders of China's Communist Party endured only fleeting international censure after their bloody suppression of the Tiananmen demonstrations in June 1989.
One might argue that this is because there are so many entrenched business interests who have an interest in glossing over bad behavior. But there are also many other reasons for official forgetfulness. The White House scolded Uzbekistan's dictator Islam Karimov for the massacre of hundreds of demonstrators in the city of Andijan in 2005 -- but that moral impulse was soon overridden by the need to maintain supply lines to U.S. troops in Afghanistan that run through Karimov's Central Asian homeland. (It's striking, indeed, that reporters were unable to extract an unambiguous condemnation of the Cairo killings from the State Department today, where a spokeswoman was only willing "to call on the military to use maximum restraint responding to protesters, just as we urge all of those demonstrating to do so peacefully." Protestors in Egypt can hardly be blamed for suspecting that the White House is bending over backwards to maintain its good relations with the Egyptian military.)