Washington ? Many Capitol Hill lawmakers are uneasy about the prospect of pre-emptive military action, and fear that President George W. Bush lacks the credibility as an international leader to sustain the kind of coalition that saw America through the first Gulf War. Instead of doing the hard, diplomatic work that his father did to build support, Bush relies on tough talk. This works at home, but offends America’s allies who feel bullied rather than consulted.

Bush initially didn’t want to bother with the United Nations, yielding only when his go-it-alone strategy seemed to backfire over the summer. Then he served notice that the United States would act unilaterally if the diplomats dithered too long. Other top administration officials are no better at wooing the kind of broad support that would give legitimacy to a potential U.S. military strike in Iraq. Defense Secretary Donald Rumsfeld refused to even meet with a German official at a recent NATO gathering in Europe as punishment for what the administration views as Germany’s anti-Americanism in opposing Bush’s bellicosity on Iraq. Vice President Dick Cheney’s trip to the Middle East last year to muster support for a war against Iraq was an abject failure.

Secretary of State Colin Powell can’t carry the case for war because he’s lost Bush’s confidence by signaling his doubts in the media. National security adviser Condoleezza Rice is too much of an academic to be persuasive, and prefers to stay in her ivory tower. That leaves British Prime Minister Tony Blair as the chief spokesman for American foreign policy. When Blair says that Iraqi President Saddam Hussein is a clear and present danger, the words carry weight in the international community. Without Blair to lend him credence, Bush would be a lonely figure on the world stage. Blair has proven himself as a loyal supporter of U.S. foreign policy, regardless of whether there is a Democrat or a Republican in the White House.

Blair is fending off opposition in his own party to maintain his alliance with Bush on the need for intervention in Iraq. There is no political gain for Blair at home, which is why he has such credibility when he speaks out. Nobody can say he is manipulating fear of Saddam for political advantage. Bush has yet to quiet the critics who suspect he has revved up the war talk to distract from a weak economy and rally the country around a national security issue where Republicans running for election might gain an advantage.

Bush’s presentation before the U.N. evoked skepticism about whether the administration has hard evidence of Saddam’s intentions and capabilities, or is driven more by a desire to settle old scores. Bush’s history in the oil business arouses suspicion in the Muslim world that striking at Iraq is a pretense for taking over the region’s oil resources.

Public opinion in Britain is running against the war, and members of Britain’s ruling Labor party are defying Blair in a way they haven’t dared since he first took office. American conservatives initially viewed the charismatic Blair as a Clinton clone, too smooth, too calculating, politically agile but not principled. He has proved his depth of character and given Bush a lifeline to the world. When Blair goes before the British Parliament and says there must be action, people pay attention. The fact that Blair has no apparent qualms in backing a potential military strike against Iraq is the most powerful argument Bush can make on Capitol Hill.

Prediction: Blair will continue to do the heavy lifting in the effort to oust Saddam Hussein.