With Americans weary of the Iraq war and U.S. elections on the horizon, Congress is struggling over how to get tough on Iran without giving President George W. Bush a blank check for a military strike.

Lawmakers have voted for some sanctions that are harsher than the White House wanted as a way of pressing Iran to give up nuclear work that the West says is aimed at building a bomb and Tehran insists is a peaceful power project.

But there is growing worry in Congress that Bush will resort to military force in Iran before leaving office in January 2009.

Congress wants to play tough, but at the same time, avoid a war, said Karim Sadjadpour of the Carnegie Endowment for International Peace.

Many lawmakers, especially those facing re-election next year, regret that they paved the way for Bush to invade Iraq with a vote authorizing force in 2002. Opinion polls show the war is increasingly unpopular with a majority of Americans.

Being tough on Iran is seen as good politics ... People can seem tough on terrorism by supporting what is seen as tough action against Iran, said Jon Wolfsthal, senior fellow at the Center for Strategic and International Studies.

At the same time there is real concern about what the Bush administration may do before it leaves office, he said. Very few people on Capitol Hill are prepared to just trust the administration to do the right thing.

Bush last week slapped sanctions on Iran's military and its financial sector, hoping to increase pressure on Tehran to stop uranium enrichment and curb what the U.S. government says are its terrorist activities.

HOUSE VOTE FOR NEW SANCTIONS

But the House of Representatives had already voted overwhelmingly for hard-nosed new sanctions that would punish energy companies that invested in Iran.

The bill by California Democratic Rep. Tom Lantos passed 397-16 on September 25, even though U.S. officials warned it would upset European countries where companies would be hit. The measure is awaiting action in the Senate.

On September 26, more than three-quarters of the Senate approved a non-binding resolution urging Bush to label the Iranian Revolutionary Guard Corps a terrorist group. Bush took similar action a month later.

But rhetoric from Bush, who said a nuclear-armed Iran could lead to World War Three, and Vice President Dick Cheney, who declared we will not allow Iran to have a nuclear weapon, triggered fresh alarm that White House was on another march to war.

Thirty senators wrote to Bush this week warning him that the Senate's Iran resolution was not meant as authority for an attack.

The letter was signed by White House contender Sen. Hillary Clinton, a New York Democrat who was slammed by opponents for voting for the resolution. One of her rivals for the Democratic presidential nomination, Illinois Sen. Barack Obama, has proposed nullifying it.

And the Senate's No. 2 Democrat, Dick Durbin of Illinois, introduced a measure stipulating that Bush must seek congressional approval before taking any military action against Iran.

I think they recognize there's not a big appetite among constituents to embark on another foreign policy adventure in the Middle East, Sadjadpour said.

Neither Republicans nor Democrats seem enthused about the prospect of a military confrontation, he said.

Even so, it's unlikely Republicans will favor resolutions insisting on congressional consent for an attack.

I don't think there's any need to even be voting on the subject of possible military action in Iran, said Senate Republican leader Mitch McConnell of Kentucky. Nobody is suggesting it.

Iraq California Congress George W. Bush