After meeting with the president, Democrats – and Republican John McCain – said they'd prefer trying the diplomatic route first.
"I believe we are on the track to a regime change in Iraq," said McCain, R-Ariz. "Exactly how that's done is not clear to me."
One member of the House Intelligence Committee complained that the president has not presented any compelling evidence for an attack on Iraq.
"I am not aware of information that would justify what they are talking about now," said Rep. Nancy Pelosi, D-Calif.
But Mr. Bush is under enormous pressure from hawks in Congress who continued beating the drums of war.
"It's time for the world to tell Saddam Hussein that his regime is over," said House Majority Whip Tom DeLay.
Asked if war was the only option, DeLay, R-Texas, said, "As far as I'm concerned it's the only option because to do nothing undermines our ability to protect the American people."
Some lawmakers feared they wouldn't be consulted before an invasion — especially after the White House counsel determined last month that congressional approval wasn't legally necessary.
Mr. Bush assured them Wednesday that they would be consulted. Senate Majority Leader Tom Daschle, D-S.D., said the president pledged to have more meetings with the leadership, make administration officials available for hearings and seek a resolution of support before beginning any military action.
"This is a debate the American people must hear, must understand," Mr. Bush said after a meeting with 18 Democratic and Republican congressional leaders. "And the world must understand, as well, that its credibility is at stake."
Mr. Bush has said no decision has been made about whether to attack Iraq. But he told lawmakers, "At an appropriate time, and after consultations with the leadership, I will seek congressional support for U.S. action to do whatever is necessary to deal with the threat posed by Saddam Hussein's regime."
House Speaker Dennis Hastert said Congress would vote before the Nov. 5 elections on how to deal with Saddam, ensuring that Iraq is a high-profile issue in the campaign for control of the House and Senate.
In an opinion piece Thursday in The Washington Post, former President Carter declared that "a unilateral war with Iraq is not the answer." He said there is an urgent need for United Nations action to force unrestricted inspections in Iraq.
"But perhaps deliberately so, this has become less likely as we alienate our necessary allies," wrote Mr. Carter. "Apparently disagreeing with the president and secretary of state, in fact, the vice president has now discounted the goal as a desirable option." Mr. Carter also criticized the U.S. government for "abandoning any sponsorship of substantive negotiations between Palestinians and Israelis."
In Berlin, German Chancellor Gerhard Schroeder said Germany is firmly opposed to military action and rebuffed calls by Britain for European nations to help apply pressure to Iraq.
"Friendship cannot mean that you do what the friend wants even if you have another opinion," Schroeder said. "Anything else would not be friendship, but submission — and I would consider that wrong."
In Cairo, Arab League chief Amr Moussa said Thursday that a strike against Iraq would "open the gates of hell" in the Middle East, and urged Baghdad to readmit weapons inspectors in coordination with the United Nations.
"We hope and we will continue to work to avert war or any military action. ... We will continue to work to avoid a military confrontation or a military action because we believe that it will open the gates of hell in the Middle East," he said at the end of a two-day Arab foreign ministers' meeting.
Mr. Bush intends to make his case for invasion when he addresses the United Nations on Sept. 12, a day after the one-year anniversary of the terrorist attacks in New York and Washington.
Mr. Bush intends to tell world leaders then that the relevance of the United Nations itself is at stake, according to an official familiar with early drafts of the speech.
Mr. Bush is seeking international support for an invasion of Iraq, something opposed by most world leaders. He will meet Saturday at Camp David with Tony Blair, the staunchest U.S. ally on Iraq. Mr. Bush said he would reach out to presidents Jacques Chirac of France, Jiang Zemin of China and Vladimir Putin of Russia — all three opposed to war.
In South Africa, Secretary of State Colin Powell said he received "a solid expression of support" from allies at a U.N. development summit.
The president is strongly considering a U.N. Security Council resolution that would set a deadline for Iraq to open its weapons sites to unfettered inspection and to apply punitive action if he refuses, administration officials said.
Iraq agreed to allow international weapons inspectors after the 1991 Persian Gulf War, but they have been barred from the country since 1998. The United States believes Saddam is developing chemical, biological and chemical weapons, which he could use himself or give to terrorists.
Iraq denounced Mr. Bush's "evil plans." Iraqi Foreign Minister Naji Sabri, speaking at the Arab foreign ministers meeting in Egypt, said: "These are whims and lies and pretexts ... all prepared with no evidence at all to support them."