Blair's proposal, an attempt to persuade a reluctant United Nations to line up behind Britain and the United States, contains six tests for Hussein, including a requirement that he admit to his country, in Arabic and on Iraqi television, that he has been hiding weapons of mass destruction.
U.S. officials hinted that new diplomatic efforts were putting them closer to getting the minimum of nine votes required for approval of the resolution.
"I wouldn't deny we are making progress, but I wouldn't lead you to believe we've got it in the bag," Richard Boucher, the State Department spokesman, told reporters in Washington.
White House spokesman Ari Fleischer said President Bush "appreciates the efforts of the United Kingdom" and said diplomats from several countries were discussing language in the resolution.
He said the president was working the phones - speaking with Russian President Vladimir V. Putin, among others - to line up support for an acceptable resolution that would authorize war.
"The president is going the last mile for diplomacy," Fleischer said. "We shall see if the other nations on the Security Council are willing to entertain that last mile."
But he indicated Bush's patience was running thin: "The president has given diplomacy a certain amount of time. He will not give it forever."
Both Britain and the United States say they believe U.N. Resolution 1441, which was passed by the Security Council in November and warned of "serious consequences" if Hussein did not disarm, gives them authority to wage war against Iraq.
Blair, though, has been in desperate search of a compromise to win a second resolution to help him politically at home, where public opinion has been mounting to pull out of a military campaign in the absence of U.N. consent.
While battling for the resolution, the prime minister has also been fighting to keep control of his Labor Party, which is deeply divided on the war.
Blair's task was made more difficult by U.S. Defense Secretary Donald H. Rumsfeld, who said Tuesday that Britain's role was "unclear," implying the United States was prepared to go to war without its ally.
The defense secretary later "clarified" his comments to say he expected British troops to fight beside their U.S. counterparts, but the anti-war faction of Blair's Labor Party seized on the original remarks as evidence that Britain is not needed in a war with Iraq and that the prime minister should take the "out" Rumsfeld provided.
Nearly all of Britain's national newspapers ignored Rumsfeld's clarification and ran front-page headlines yesterday declaring a divide between the United States and its closest ally.
"Blair crisis over U.S. rift," said the Evening Standard. "U.S. is ready to launch war without Britain," said the Daily Telegraph. "Blair staring at disaster as U.N. refuses to back war and Bush says he may attack without him," joined the Daily Mirror.
"If this was Donald Rumsfeld trying to help Tony Blair, he had better not consider a career in the diplomatic service," wrote Nick Assinder, political correspondent of the British Broadcasting Corp. "With one brief comment he has managed to blow a series of massive holes in the prime minister's armour."
But while fielding questions yesterday in the House of Commons, Blair made clear that his willingness to go to war has not been diminished by threats to his political career and that, regardless of Rumsfeld's view, he is committed to disarming Iraq by force if necessary. Britain has about 40,000 troops in the Persian Gulf region.
"What is at stake here is not whether the United States goes alone or not," he said. "It is whether the international community is prepared to back up the clear instruction it gave to Saddam Hussein with the necessary action. That is why I am committed to hold firm to the course we have set out."