The United States has made considerable progress in its war to uproot Osama bin Laden's terrorist network and the Taliban regime that protects it in Afghanistan. The Taliban's rule collapsed in northern Afghanistan after five weeks of bombing and the subsequent rapid advance of the United Front (or Northern Alliance) opposition coalition. The Taliban has fallen back in disarray to its stronghold of Kandahar in southern Afghanistan. This will make it easier to find and destroy bin Laden's terrorist infrastructure--the paramount U.S. goal in Afghanistan.

But the war in Afghanistan is far from over. In fact, the next phase of the war may be much more difficult if the foreign members of the Taliban choose to fight to the death or if the Taliban reverts to guerrilla warfare in rugged southern regions hostile to the Northern Alliance, as some of its leaders have threatened. The American counterterrorist campaign may be further complicated by the intensifying power struggle among the various elements of the opposition coalition, returning exiles, and emerging Pushtun tribal militias and their respective foreign backers, all of whom seek to fill the vacuum left by the Taliban's implosion.

To sustain and build on its initial victories, the United States must press ahead relentlessly with its military campaign to score a knockout blow against the Taliban leadership and roll up bin Laden's network as soon as possible. Washington also must gain the long-term cooperation of non-Taliban Pushtun leaders in fighting Islamic extremism and building a stable post-Taliban government. The December 5 Bonn agreement between Afghan factions that set up a provisional administration is a good first step.

The challenge for Washington will be to turn the rout of the Taliban into a decisive military victory and then ensure that the post-war political structure that emerges prevents Islamic extremists such as the Taliban and bin Laden from returning to roost in Afghanistan. To achieve these goals, the United States should:

• Work closely with the United Front and help it maintain its battlefield dominance to defeat the Taliban decisively and eradicate bin Laden's terrorist network . Keeping the United Front at arm's length and restraining its military advances to appease Pakistan will only lengthen the war and require a greater commitment of American troops.
  
  
• Step up efforts to enlist the emerging non-Taliban Pushtun leaders in southern Afghanistan as allies in the war against the Taliban and al-Qaeda and include them in the process of building a post-Taliban Afghanistan . The Pushtun ethnic group historically has played a leading role in Afghan politics, and there can be no lasting political stability without the substantial political participation of this group. The United Front alone is not strong enough to purge Afghanistan of Islamic extremists and guard against their return.
  
  
• Encourage the building of a decentralized post-war government to give all Afghan groups strong incentives to cooperate and to avoid factional feuding. The United Nations-sponsored Bonn agreement has laid the groundwork for building a post-war government, but this fragile consensus could be threatened by political bickering. Empowering the provincial governments and giving them substantial autonomy and access to reconstruction aid would reduce the possibility of an all-out power struggle over the control of state institutions centered in Kabul. A decentralized government guided by the principles of federalism also would have the beneficial effect of allowing a new generation of Afghan leaders to advance within the power structure through political competition rather than military domination. Taliban leaders should be excluded from this government.
  
  
• Ensure that Afghans become active stakeholders, not passive clients of United Nations bureaucrats, in post-war reconstruction. The United Nations can play a supportive role in Afghanistan's post-war reconstruction, but it should not be allowed to supplant Afghan sovereignty and self-determination. Nor should it seek to apply to Afghanistan the flawed model of U.N. administration practiced in Bosnia. Given the appropriate tools and access to resources, Afghans are capable of cooperating to rebuild their economy and construct a stable government. Genuine nation-building can be accomplished only from the bottom up; it cannot be administered from the top down.
  
  
• Restore Afghanistan's historic role as a neutral buffer state and halt its neighbors from meddling in its internal affairs. Washington should press outside powers to halt their intensifying proxy wars in Afghanistan and respect Afghan independence. If possible, it should negotiate a treaty between Afghanistan, all six of its neighbors, Russia, and the United States guaranteeing that Afghan territory would not be used as a base to threaten any other state.
  
  
• Avoid tying down U.S. troops in any open-ended peacekeeping mission in Afghanistan. American military power and resources should be focused on the next phases of the war against international terrorism. The Bonn agreement calls for a multinational peacekeeping force to be deployed in Kabul and eventually in other areas. These peacekeeping troops should come from distant Muslim countries. But ultimately, peacekeeping can be accomplished and sustained effectively only by Afghans, not by foreigners.

James Phillips is a Research Fellow in Middle Eastern Affairs in the Kathryn and Shelby Cullom Davis Institute for International Studies at The Heritage Foundation.