SAUL LOEB/AFP/Getty Images

Old hand: Biden receives Kosovan President Hashim Thaci at the White House in February.

Something is terribly wrong with Joe Biden visiting the Balkans next week. It isn't his expertise that is at issue. Few Americans understand the region better than Biden, who had the temerity to call Slobodan Milosevic, the late Serbian dictator, a "war criminal," to his face. The problem is that a visit from the vice president of the United States is even needed nine years after Milosevic lost power, a decade after NATO intervened in Kosovo, and 14 years after determined U.S. diplomacy ended the war in Bosnia.

Sadly, Biden's visit to Serbia, Kosovo, and, most especially, Bosnia, is all too necessary. The reason is simple: Europe is still not up to resolving its own security problems. Brussels is indifferent at best, and divided at worst, when it comes to the pressing issues in the Balkans. Five EU states still do not recognize Kosovo. The European Union lacks a viable policy toward Bosnia, leaving Washington to lobby most consistently for the steps that would bring the country into the EU.

By default, U.S. leadership remains indispensable in the region. Fortunately, it is quite welcome. Biden will get a warm reception in all three countries, including from Serbia's leaders, who are eager to open a new chapter in relations with the United States.

But the challenges Biden will face are serious and complex. The most acute is Bosnia, a country whose chronic ethnic divisions have defied one of the most intensive, multilateral nation-building efforts ever attempted. Last year, for the first time since the war ended, there was anxious worry in Sarajevo about renewed conflict. Even if the parties never pick up arms again, Bosnia risks permanent stagnation, a quite plausible scenario that would put the substantial American investment -- and continuing American interests -- in Bosnia at risk. In the words of a former senior Bosnian official, without swift reform the country is doomed to become an "economic colony" of its neighbors, supplying cheap labor from its chronically underperforming economy. Instead of an inevitable EU member, Bosnia is more likely to remain an unwelcome, dysfunctional and divided country, with an aggrieved Bosniak (Muslim) plurality, a frustrated, increasingly defensive Serb entity, and an anxious, existentially threatened Croat population.  

Unlike its predecessor, the Obama administration is attuned to the need to quickly get a handle on the situation in Bosnia. All three parties still look to Washington for leadership. The question is: How can the United States maximize its influence before ceding to the EU sole control of international supervision in the country? There are two options. The first is to to simply "get Bosnia through" to the 2010 elections without further slippage. But the United States will still be saddled with the problem of what to about Bosnia once Brussels takes over and U.S. influence is diminished. It is unlikely that next year's elections -- the country's tenth -- will produce true moderates or transform relationships among divided Serbs, Croats, and Bosniaks.  Once the country enters its election cycle early in 2010, politics will again revolve around defending parochial ethnic interests -- squelching any opportunity for productive dialogue. Washington faces the risk of being sidelined while Bosnia continues to languish under ineffective European stewardship.

The second and better option is to finally fix the core problem in Bosnia: the unresolved relationship between Republika Srpska (RS), the Serb entity that emerged from the war, and the central state that Serbs see as "Muslim dominated." This means opening up the constitution to fundamental change, something the Serbs are reluctant to do. They understand that any move to strengthen the central government will necessarily weaken Republika Srpska. Getting the Serbs and their Bosniak and Croat counterparts to negotiate seriously on the constitution will require a game-changer, something that will reward cooperation and penalize intransigence.

That game-changer is accelerated NATO membership. Traditionally, as in the Baltics, NATO offers the ultimate protection against external threats; in divided Balkan states like Bosnia (and Macedonia), NATO represents a guarantee of internal cohesion. This is as important for Serbs, whose overriding objective is to preserve their entity, Republika Srpska, as it is for Bosniaks, whose overriding objective, shared by many Croats, is to preserve the integrity of the state. In short, NATO membership both protects Republika Srpska and prevents it from seceding.  Instead of "holding out for the next round" (of fighting, negotiation or attempted secession), the parties will proceed from a platform of permanence. In the words of the leader of a prominent Bosnian party, "NATO membership takes fear out of the equation." And by doing so, the prospects for reaching a compromise on difficult constitutional issues would be dramatically improved.

Unlike EU membership, accession to NATO is something that Bosnia can achieve in the near term, even by the next alliance summit at the end of 2010, given intensified support. To be sure, neither a membership action plan nor full membership will be given "for free"; Bosnia parties will have to do their part, including making substantial reform of the constitution, which locks the parties in a paralyzing, zero-sum relationship. Only the tangible promise of fixed-date membership will goad them to compromise - not the vague, passive hope of eventually crossing an "open door."

To skeptics, RS Prime Minister Milorad Dodik's recent call for Serb troops to pull out from Bosnia's participation in NATO exercises in Georgia offers proof that Banja Luka has no serious interest in joining the alliance. Dodik's ploy was indeed a grave blow - but against the authority of the state of Bosnia-Herzegovina much more than against NATO. His decision was derided by other Serb parties. Even the Serb member of Bosnia's presidency, who comes from the same party as Dodik, did not defend his position. Rather than expect EU supervision and the possibility of eventual EU membership to produce evolution in attitudes, it is imperative to present the parties with a serious choice now: NATO membership and a secure, normal country - or permanent dysfunction and insecurity. In the unlikely event that Dodik rejects the offer, it will at least elicit clarity about his true intentions.

NATO membership has been the way-station to the EU for every Eastern European member of the union. Accelerating NATO membership will boost Bosnia's EU prospects, spurring Brussels to energize its approach. And once Bosnia -- with Republika Srpska intact -- joins NATO, the nascent debate in Serbia on joining the alliance will be transformed. No longer will virulent nationalists in Belgrade be able to sustain the argument that NATO membership and Serb security are incompatible. And as Serbia moves closer to both NATO and the EU, rapprochement with Kosovo is inevitable.

When Biden visits Serbia and Kosovo, he will need to cite the violent confrontation that occurred last week between Serbs and Albanians in the Serb-controlled north of the fledgling Republic of Kosovo. (In general, warnings of calamity about Kosovo's year-old independence have not come to pass. Serbia has taken its opposition to independence  to the courts. While Belgrade awaits its day in the International Court of Justice, Pristina continues to slowly accumulate international recognition.) Unlike in Bosnia, the key in both Kosovo and Serbia is to promote internal democratic processes and cooperation with international actors, not reach for a dramatic breakthrough just yet. Washington should support the genuine desire in each country to join Euro-Atlantic institutions, a development that will foster accommodation.

Until Europe finally shows the will and capability to deal with its troublesome corner, U.S. leadership will remain indispensable. And so will more visits by Vice President Biden and his colleagues.