If America is to have a chance now to begin to bring the disastrous Iraq war to an end, it is critical that Congress not lose its nerve in its exchanges with President Bush.

The way it stands, Mr. Bush is asking for another $100 billion -- on top of an already hefty $533 billion Department of Defense budget -- to wage the Iraq war. The Senate and the House have both passed bills providing for that funding, but with conditions attached. Both bills require the administration to set a timetable for withdrawal of U.S. troops from Iraq.

If Congress doesn't lose its nerve, Mr. Bush is faced with two unattractive (to him) alternatives. Either he signs a bill and becomes legally required to set and implement a withdrawal timetable. Or he vetoes the bill, as he has promised to do, and thus either doesn't get the new $100 billion for the war or has to find the funding to continue it elsewhere in the defense budget. Either way, it can be said that the United States will be drawing nearer the end of this long war, so costly in American blood and treasure.

It is absolutely essential that Congress hang onto its courage and not let the foolish blustering of Mr. Bush and Vice President Dick Cheney chase them away from what is a strong political and legislative position. Apart from doing what is best for the country, Congress will also have firmly asserted the role of the legislative branch of government in carrying out the will of the American people, which was expressed at the ballot box in November and in the polls since.

How Mr. Bush and his cohorts can maintain that there is still work for brave American forces to do in Iraq in the face of recent developments is a triumph of stubborn folly over wise decision-making. We have seen in recent days a bomb go off in the Iraqi parliament in Baghdad's highly protected Green Zone, the withdrawal of major Shiite support for Shiite Prime Minister Nouri Kamel al-Maliki's government and horrendous attacks with high death tolls in Baghdad despite Mr. Bush's "surge" of troops in the Iraqi capital. Of course, all of this happens more than four years after the war started.

Congress can fix this situation, and should. All that its members have to do is stand firm.