No speech – regardless of how well written or powerfully delivered it may be – can be expected to restore the president's credibility or win over a nation that has grown disillusioned after almost four years of war and more than 3,000 American deaths. Only clear signs of progress on the streets of Samarra and the neighborhoods of Baghdad could do that.

And there was little in what he said last night that had not been leaked in advance or said by him many times in previous speeches.

“It was not very persuasive,” said Gordon Adams, director of Security Policy Studies at George Washington University. “We don't control the flow of events. So in the end, almost whatever he does, we're the prisoners of the situation on the ground.”

Fundamental questions were left at the end of the White House address. Are the additional 21,500 troops just the first of what will be many escalations? Or are they truly only a “surge,” which suggests a small and short-lived augmentation? How was the figure 21,500 reached when those who had been arguing for this surge have long contended that anything less than 30,000 would invite failure?

And – most fundamental of all – is this really a change in strategy or simply a change in tactics? The president called it a change in strategy, but it is hard to see what is different from his longstanding policy of keeping a large number of American troops in Iraq until the Iraqi government is able to maintain security on its own.

“All of these elements have been around before,” said longtime Washington presidential analyst Stephen Hess of George Washington University. “New people will do it; new money will be involved. Some new troops, of course. And then all we can do is hope that the situation improves.”

That is not to dismiss the significant tactical shifts outlined by the president in what Hess called a “very somber, sober speech.” Perhaps most important was his sternest warning yet to the Iraqi government of Prime Minister Nouri al-Maliki that the American commitment “is not open-ended.”

How much of a shift this represents will not be known until the first time American troops want to crack down on Shiite militias in Sadr City and request permission from al-Maliki.

For Bush, it cannot be very reassuring to find his legacy now tied to the actions of al-Maliki, someone who has repeatedly disappointed the White House. But that is where he finds himself as he enters his seventh year in office. His presidency “is on the line,” said David Keene, chairman of the American Conservative Union.

“He is in a deep hole and trying to dig himself out,” Keene said, lamenting that Americans are confused about the purpose of the war. Bush had to use the speech “to show that he has a plan and that sending more troops is part of a sensible plan. Sending more troops by itself is not a plan,” said Keene.

Even before Bush spoke, though, it was clear that the plan would not be embraced in Congress. No one expects the newly empowered Democrats on Capitol Hill to be able to block the escalation. But with their new majorities in Congress they can demand answers that weren't given in the White House address.

More troubling for the White House, a growing number of Republicans are not only distancing themselves from Bush's Iraq policy but speaking out against it.

However much Democrats might wish it, though, the problem is not Bush's alone.

Anti-war activists like Cindy Sheehan have sent a loud and clear message – they are demanding that Congress end the war now.

Democrats already “face significant problems from their own base,” said Norman Ornstein, a congressional expert at the American Enterprise Institute. “From their perspective this was an election about Iraq. . . . And, frankly, they are not going to accept any excuses.”

Democrats have ample incentives to cooperate with Bush on a range of problems, including immigration, energy and health care. But that bipartisan spirit appears mortgaged to events in Iraq and could evaporate if a worsening military enterprise prompts a constitutional clash over Bush's war policies.

“Iraq is like the nine million pound gorilla that could crowd everything else out, and . . . poison the well for everything else,” Ornstein said.

Perhaps mindful of that, Bush used the speech to appeal for bipartisan cooperation.

There is no doubt, though, that this escalation is a gamble and threatens the chances for true bipartisanship. Keene likened the president to a poker player who “has lost so many hands that he's way down. So now he stakes everything on the next card and has to go all in. If the right card comes up, he'll go home a winner, but if it doesn't, it's all over.”