Washington ? President Bush wasn’t on the ballot, but he may have been the biggest loser in Tuesday’s elections.

After crisscrossing the country on behalf of Republicans, Bush suffered a rebuke from voters that left him politically weaker than he’s ever been. Democrats took control of the House of Representatives for the first time since 1994. Bush will return to work today as a lame-duck president, facing challenges that could make his final two years in office far more difficult than his first six.

Bush, who watched the returns at the White House with friends and political adviser Karl Rove, had no immediate reaction to the outcome. He’ll hold a news conference at 1 p.m. today that’s likely to bear little resemblance to his buoyant performance after the last national elections.

Two years ago, Bush claimed to have gained political capital from elections that returned him to office and increased Republican majorities in the House of Representatives and the Senate. The question now is whether he has enough left in his account to function effectively.

Political analysts say it’s too early to count him out. “The president is not going to be a hapless giant. The powers of the presidency are tremendous, and they remain tremendous,” said Stephen Hess, a presidential scholar at the Brookings Institution, a center-left think tank.

Still, there’s no question that Bush suffered a setback that will diminish his standing at home and abroad, at least in the short term.

House loss hurts

The Democratic takeover of the House eliminated Bush’s best ally in Washington. Instead of a compliant, Republican-controlled chamber, he’ll face a combative legislative body led by Democrats nursing six years of grievances against him.

The Senate, seldom as loyal to Bush as the House was, will be even less reliable than it has been. Although the final party lineup remained in doubt late Tuesday, the only unresolved question was how many seats Republicans would lose. Even if they retain a majority, it will be razor-thin – and Republican senators have been put on notice by the voters.

Democrats won’t have enough votes in Congress to impose their plans with legislation, especially over Bush’s veto, but they’ll have enough to bottle up the president’s initiatives and block controversial appointees to the Supreme Court or key administration jobs. Control of the House also would give them the power to launch investigations into every aspect of administration policy.

“They can’t change anything, but they can investigate everything. It isn’t going to get any more pleasant for him,” Hess said. “All the elements of gridlock are in place.”

On the world stage, Bush is likely to be viewed as a wounded leader, especially by his critics. The first test of his international clout will come next week, when he travels to Asia for an international summit that will include talks on how to deal with North Korea’s nuclear ambitions.

The Iraq factor

Then there’s Iraq. If the election was a referendum on Bush’s handling of it – and polls indicate that it was – the president lost big. No other issue was more important to voters in pre-election polls. Dissatisfaction with Bush’s Iraq policy was particularly strong among Democrats and independents.

“I think today’s story is really, by and large, the story of Iraq and an unpopular war,” Sen. Arlen Specter, R-Pa., told MSNBC even before the votes were counted. “I think you’re going to see a new course charted.”

Up to now, Bush has shown little interest in changing course – in Iraq or in his domestic policy. Will Tuesday’s election lead him to a different path?

One clue to Bush’s thinking will be the fate of Defense Secretary Donald H. Rumsfeld, who’s become a target of bipartisan criticism. Bush declared his support for Rumsfeld just last week, but the pre-election endorsement might make it easier for Rumsfeld to say that he’s leaving voluntarily.

No matter what happens with Rumsfeld, Bush can expect growing pressure to change his Iraq strategy if the situation fails to improve.