With growing frequency, the broad middle of Congress has asserted that political, rather than military, solutions are the primary means for an effective departure for U.S. troops from Iraq. So the Senate’s refusal Monday to vote on a resolution that rejected the president’s troop build-up was a disappointment, but that vote would not be nearly as useful as devoting similar energy to considering which nonmilitary course the nation should attempt.

For reasons explained in the declassified portion of the recent National Intelligence Estimate, the challenge to Iraq includes solving the growing split between Sunni and Shia, a divide deepened by the historical “subordination to Sunni political, social and economic domination” that have left Shia insecure with their hold on power. The Sunni rejection of the central government and their minority status is also listed by the NIE, as is the absence of unifying leaders among the two groups.

These are not problems – unlike, for instance, the al-Qaida presence in al-Anbar province – likely to be solved militarily. A greater show of U.S. force in support of a Shia-dominated government might even make things worse. Instead, expanded diplomacy, third parties from the region who could advance the ideas of fair treatment of civilians and who could support a government seen as broadly representative of all Iraqis would do much more to bring calm.

Iraq and its neighbors are the entities most likely to end the fighting, as the Baker-Hamilton commission outlined. Including the region in a search for stability in conjunction with U.S. military disengagement should be at the forefront of U.S. plans, with heightened military action viewed as a failure of that process.

Economics matters as well. Sen. Susan Collins, one of the sponsors of the resolution in the Senate this week, has observed before that finding employment for Iraqi men could lower the likelihood that they would accept money to join in the Sunni-Shia battles. The Bush administration has used its Millennium program to send development aid to countries showing signs of democratic progress. A similar reward system may work in Iraq, starting in cities outside of Baghdad and working toward it.

This doesn’t mean the United States should simply walk away from a calamity it helped create. The NIE makes clear, “If such a rapid withdrawal were to take place, we judge that the ISF [Iraqi Security Forces] would be unlikely to survive as a nonsectarian national institution; neighboring countries – invited by Iraqi factions or unilaterally – might intervene openly in the conflict; massive civilian casualties and forced population displacement would be probable …”

From the beginning of the war in Iraq nearly four years ago, various experts, officials and former officials talked about windows of opportunity for bringing freedom and democracy to Iraq, then electing a government strong enough to be effective, then improving security. One by one, the NIE document suggests, those windows are closing or have closed.

Without precipitous withdrawal, the emphasis from the United States must be on political solutions. Congress can provide the forum for those ideas through hearings, testimony and debate. The failed resolution was one way to begin that process, but what comes next could matter more.