Before the November elections, many Democratic candidates and legal academics insisted that the Iraq war was illegal and that only Congress, not the president, had the power to manage it under the Constitution. Interestingly, now that Democrats control Capitol Hill, they are fretting that if Congress were to try to cut back on funds or troop levels, it might be, well, unconstitutional. Democrats are suddenly acknowledging that the commander in chief and executive branch may be better off without their micromanagement, after all.

Of course, they haven't been silent about the war: Both the House and Senate recently have been political circuses, juggling various bills that proposed to "rein in" the president. But behind all the bluster, the one thing all the major Democratic proposals have in common is that they are purely symbolic resolutions, with all the force of a postcard. (Two other Democratic Senate proposals that have actual teeth — one by Russell Feingold, D-Wis., to cut off money for the war, another by Barack Obama, D-Ill., to mandate troop reductions — were ignored by the leadership.)

The fact is, Congress has every power to end the war — if it really wanted to. It has the power of the purse. Its British forebears in Parliament micromanaged the monarchy quite a bit, for instance by making money (the "sinews of war") contingent on attacking one country and making peace with another. And there is more direct precedent: In 1973, Congress affirmatively acted to cut off funds for Vietnam. It also cut off money for the Nicaraguan Contras with the Boland Amendment in 1982.

Not only could Congress cut off money, it could require scheduled troop withdrawals, shrink or eliminate units, or freeze weapons supplies. It could even repeal or amend the authorization to use force it passed in 2002.

A pullout, however, would have no chance of success, because its supporters are likely to lack the two-thirds majority necessary to override a presidential veto. But to stop President Bush's proposed troop surge, Congress doesn't have to do anything. It can just sit back and fail to enact the periodic supplemental spending measures required to keep the war going. Congress has wielded considerable power by just threatening such measures, as with President James K. Polk in the Mexican-American War and President Ronald Reagan in Lebanon after the 1983 barracks bombing.

The Constitution doesn't pick winners. It leaves it to the three branches to use their unique powers to struggle for supremacy. James Madison, the leading intellectual force behind the Constitution, rebutted Patrick Henry's firebrand attack on executive war powers during the Virginia ratifying convention by reminding him that Congress could control any renegade president by stopping the flow of money.

But with power comes responsibility. The truth is that this Congress is not sure what to do in Iraq. Its hesitation reflects America's uncertainty and divisions. Anti-war bluster is high at the moment, echoing popular frustration and grim news from Baghdad.

Our elected representatives know, however, that policy can't be made by poll. Most also understand that leaving Iraq to a sectarian power struggle would break our word and lead to slaughter. A failed state in Iraq would breed more terrorism, not less, by becoming a haven for more radical training camps.

Most in Congress, in fact, are not eager to replay Vietnam. The United States has had far fewer casualties in this conflict. Our national security interests here are high. If we falter now, it would be read as a "defeat" and embolden more terrorist attacks on us. Once again, the world would begin to doubt American strength. This would undermine our ability to conduct credible diplomacy, while electrifying Islamists to further jihad.

The truth is that the Democrats in Congress would rather sit back and let the president take the heat in war than do anything risky. That way they get to prepare for the next election while pointing fingers of blame and spinning conspiracy theories. It is odd to see the Democratic Party turning toward isolationism, bonding with paleoconservatives, and so bitterly averse to the ideals of democratic nation-building.

War is not about instant gratification in a hail of klieg lights, our truncated Gulf War notwithstanding. In an interdependent, globalized world, we can't shrug our shoulders and shirk in the war on terrorism. America made a fundamental change in foreign policy after the Sept. 11 attacks: to support and spread democracy. The House speaker, Nancy Pelosi, D-Calif., should understand this well. She made her national reputation as a junior representative in the 1980s criticizing the Chinese dictatorship after the Tiananmen Square massacre.

Perhaps it was inevitable that the public would soon tire of war and engage in overheated accusations of bad faith. It is quite right that Congress review, and consider, from its unique perspective, what changes, if any, it now wants to make. If Congress really believes the Bush administration has set us on the wrong course, it can act tomorrow to cut the sinews of war in Iraq. But its failure to do so seems an acknowledgment that the consequences would be far worse than what we face now.

Lynn Chu is a New York lawyer. John Yoo, a deputy assistant attorney general from 2001-03, is a law professor at the University of California at Berkeley and a visiting scholar at the American Enterprise Institute.