A year and a half ago, I voted to give President Bush the authority to use force in Iraq. I still believe my vote was just—but the president's use of that authority was unwise in ways I never imagined. I've served with seven presidents during my 32 years in the Senate. Four of them—Jimmy Carter, Ronald Reagan, Bill Clinton, and George W. Bush—were governors who came to office with virtually no foreign policy experience. I assumed that Bush would do what his predecessors had done: pick the smartest people on his side of the aisle, encourage them to argue and advocate--and keep an open mind.

Consequently, I thought I could be more effective working behind the scenes with those in the administration who generally shared my views than I could lobbing partisan bombs in public. I was encouraged in this course by the president's initial reaction to September 11: Instead of lashing out, he looked for international support, building a case and a coalition before attacking Afghanistan. Conferring regularly with Secretary of State Colin Powell, Deputy Secretary of State Richard Armitage, and national security adviser Condoleezza Rice, I kept most of my criticism private and publicly praised the administration when it did what I thought was right, to the occasional consternation of some of my Democratic colleagues.

In the long run-up to Iraq, I expected the president to follow a similar course, siding not with the ideologues in his administration but with the cooler heads in Powell's camp and with the political hands in Karl Rove's shop (polling data showed the American people wanted Bush to go to Congress and the United Nations and to try everything short of war before invading Iraq).

At first, that is what he did. He resisted the advice of some in his administration to attack Iraq immediately after September 11. He ignored those who urged him to bypass the United Nations, and he similarly rejected the advice of his own White House legal counsel, who said it was not necessary to go to Capitol Hill for support.

When the president did come to Congress in September 2002, authorizing the use of force made sense. Following the 1991 Gulf war, the United Nations had ordered Iraq to declare and destroy its weapons of mass destruction capabilities unconditionally. But, instead of doing so, Saddam Hussein spent a decade playing cat and mouse with the U.N. inspectors sent to verify his compliance with the Security Council's demands. The international community's need to enforce these U.N. resolutions provided a compelling case for war. After all, absent enforcement, such rules would become meaningless, and the international system of laws and norms, which benefits the United States more than any other country, would be badly undermined.

To be sure, many others cheat on or ignore the rules. But Iraq was the perfect storm. Saddam was a sadistic dictator who had used chemical weapons against the Kurds and the Iranians, murdered tens of thousands of Shia, and fired Scud missiles at Israel. He posed a permanent threat to his neighbors. If we had allowed the sanctions system to collapse, or even atrophy, and left Saddam alone for five years with billions of dollars in oil revenue, I'm convinced he would have acquired a nuclear weapon—intelligence suggested he still wanted one—thereby dramatically changing the strategic equation in the Middle East.

The draft resolution the White House initially sent to Congress would have given the president extraordinarily broad authority to wage war. Senator Richard Lugar and I joined forces to significantly restrict that mandate. While the alternative resolution we proposed was not enacted, it helped force the administration to accept more limited terms. The objective of the authorization Congress ultimately endorsed was disarmament, not regime change. The rationale was enforcement of the relevant U.N. resolutions as opposed to preemption of a gathering threat. The scope of the authorization was narrowed from allowing Bush to use force anywhere in the Middle East to Iraq specifically. And the desirability of enlisting international support was made very clear. In voting for the resolution, I believed Congress was giving the president a strong hand to play at the United Nations whereby he could convince the world to speak with one voice to Saddam: Disarm or be disarmed. If he failed to listen and forced us to act, at least we would have the world with us.

But, as pragmatists in the administration like Powell labored to keep the focus on enforcement, the ideologues were trying to use Iraq to ensconce a new doctrine for U.S. foreign policy: military preemption. The right to act preemptively against an imminent threat has always been a weapon in our foreign policy arsenal. And, while deterrence and containment got us through the cold war, after September 11 there was legitimate concern that they would not suffice against a stateless enemy with WMD. Unfortunately, the administration tried to turn preemption from a necessary option to a one-size-fits-all strategy--a strategy to which other countries roundly objected. Using Iraq as the test case for this new doctrine made little sense because Iraq posed no near-term threat to U.S. security, and it made it infinitely harder for us to get international backing, thereby planting the seeds for some of our current troubles.

Nevertheless, by the end of 2002, the president had sided with the ideologues. He allowed military strategy to trump diplomatic efforts. He hyped intelligence about Iraq's weapons of mass destruction programs to create a sense of urgency. And he gave up on securing more international support when he abandoned the effort to pass a second Security Council resolution. As a result, we rushed to war on misguided premises. We're paying a price for that haste today.

I'VE ASKED MYSELF many times whether there is more Congress could and should have done to slow the rush to war, even after we authorized the use of force, but the truth is that many of us repeatedly warned the administration about the mistakes it was making.

First, we urged the administration to plan for the day after an invasion of Iraq. Eight months before the war, Lugar and I wrote in The New York Times, "[W]hen Saddam Hussein is gone, what would be our responsibilities? This question has not been explored but may prove to be the most critical. ...Given Iraq's strategic location, its large oil reserves and the suffering of the Iraqi people, we cannot afford to replace a despot with chaos. We need to assess what it would take to rebuild Iraq economically and politically." Experts at hearings we convened, think-tank studies, and even some in the administration itself--such as the authors of the State Department's Future of Iraq Project--predicted many of the problems we now face: the sorry state of Iraq's infrastructure, the likelihood of postwar looting and resistance, the impossibility that Iraq's oil revenue would pay for reconstruction, the need for 5,000 international police to train the Iraqis, and the folly of relying on exiles with no constituencies in Iraq.

Second, many of us implored the administration to build an effective coalition. Not because we needed a single foreign soldier to win the war, but because we needed them to secure the peace and to increase the legitimacy of our temporary, but necessary, occupation of Iraq. Because Iraq posed no imminent threat to our security, we could have taken the time to do it right. For some of our allies, such as France and Germany, war probably was never an option, but, according to my sources (and many reports in the media), for the price of a 30-day delay, we could have convinced a majority of the Security Council to support a second U.N. resolution.

Third, many in Congress questioned the administration's plan to go into Iraq with relatively few troops in order to validate a new theory of warfare and invalidate the Powell Doctrine, which called for the use of overwhelming force in any conflict. Army Chief of Staff General Eric Shinseki was ridiculed for suggesting it would take several hundred thousand troops to secure Iraq. He looks prescient today. The failure to heed such warnings made it difficult to secure post-Saddam Iraq and produced a power vacuum that was filled by militias, insurgents, and criminals.

Fourth, many of us warned the administration that it would take years, not months, to train Iraqis to provide for their own security. When Senators Chuck Hagel, Dick Lugar, and I went to Baghdad last summer, American experts on the ground told us it would take five years to train an Iraqi police force of 75, 000 and three years to train an Iraqi army of 40,000. But the administration insisted on putting 200,000 Iraqis in uniform right away, and, as a result, only about 10 percent of the police and army now operating in Iraq have been fully trained. Virtually none are adequately equipped. While many have acted with incredible bravery, others have abandoned their posts, and some have even taken up arms against us.

In the months following the war, many of us have sounded like broken records, repeatedly calling on the president to unite the international community in helping reconstruct Iraq. At the end of major combat operations, when our apparent success gave us the high ground, many who sat out the war were ready to help--if we had just asked. Both France and Germany publicly volunteered police trainers, for example, and last December, French President Jacques Chirac told me he would support nato involvement in Iraq, though it's clear today that France is very unlikely to send troops. Instead of soliciting such assistance, the administration tried to deny its critics postwar reconstruction contracts and served "freedom toast" on Air Force One. Maybe there was no way to convince France and Germany to send troops to Iraq. But, since Saddam was toppled, we've denied ourselves the help of tens of thousands of Indians, Pakistanis, Bangladeshis, Turks, and others. I hope the administration's belated success in securing a new U.N. resolution begins to change that dynamic.

MUCH HAS BEEN said about the potential consequences of failure in Iraq—how it would provide a new haven for terrorists, deal a blow to reformers and modernizers throughout the region, and encourage radicals in Egypt, Jordan, and Saudi Arabia. But perhaps failure's most pernicious legacy will be a further hardening of the Vietnam syndrome that afflicts some in the Democratic Party—a distrust of the use of American power. [Editor's Note: The preceding sentence has been modified from the version that appeared in the print edition.]

That syndrome is one reason why, from day one, many of us in Congress pressed the president to level with the American people about what would be required to prevail in Iraq. But he didn't. He didn't tell them that well over 100,000 troops would be needed for well over two years. He didn't tell them the cost would surpass $200 billion—and far exceed Iraq's oil revenue. He didn't tell them that our children and grandchildren would pay the bill because of his refusal to rescind even a small portion of the tax cut he gave to the wealthiest 1 percent of Americans. He didn't tell them that, even after paying such a heavy price, success was not assured, because no one had ever succeeded at forcibly democratizing a nation in the Middle East, let alone an entire region.

As a result, today those who recognize that we must persevere in Iraq risk losing public support. Americans sense that our policy is adrift and that we do not have a plan for success. Worse, they may conclude that this is what happens when we venture abroad. Someday, probably sooner rather than later, there will be another Slobodan Milosevic or another Saddam, and the profound mistakes in Iraq will make it harder to generate domestic and international political support for the use of force. That is a legacy we can ill afford.

Maybe, as some argue, so many mistakes have been made in Iraq that it is impossible to turn the corner. Anti-American attitudes and a nascent warlordism may already be so deeply entrenched that there is little we can do to succeed. It would be foolhardy to deny that possibility. But it would be even more foolhardy, and dangerous, to accept failure as inevitable and move to cut our losses. Despite the naysayers, it is not too late. But only the president can alter our course in Iraq. As he did when Congress first authorized him to use force, the president has the choice of using his power effectively or squandering it to satisfy ideological predilections. Let us hope he has grown wiser in the past year.

This article originally ran in the June 28, 2004, issue of the magazine.