WASHINGTON (AP) — It could be campaign-year jitters.US President George W. Bush’s controversial eavesdropping program has irritated congressional Democrats and even some Republicans.

To some, the shift is pure politics as lawmakers worry about the November elections or look ahead to 2008. They are emboldened by fundamental legal questions about the National Security Agency’s monitoring and Bush’s weak public support on terrorism, once his bread-and-butter issue.

To others, it is Congress reasserting itself as an equal branch of government.

“This is an institutional confrontation between Congress and the White House,” Tom Newcomb said. He spent 25 years in national security in a trifecta across all three branches, including working for CIA Director Porter Goss when he chaired the House Intelligence Committee.

Not a single lawmaker briefed on the NSA programme has said the monitoring should end. But many Democrats and a growing number of Republicans are questioning the legal underpinnings of Bush’s directive authorising the eavesdropping without court approval.

Bush has said he has the inherent authority as president and, he says, Congress bolstered that power with a September 2001 resolution approving the use of military force to go after those responsible for the September 11 attacks.

Speaking on Friday, Bush said he’s doing “the right thing” with the NSA programme. “Washington is a town that says, ‘You didn’t connect the dots’, and when you do connect the dots says, ‘You’re doing the wrong thing’.”

But Democrats and — notably — some Republicans say Bush’s legal arguments are a stretch.

Some of those Republicans will not face voters until 2008, including Senate Judiciary Chairman Arlen Specter of Pennsylvania, Sen. Susan Collins of Maine, and Sen. Lindsey Graham of South Carolina.

Specter and Collins are part of a dwindling breed of Republican moderates. Graham, who also has tangled with the White House, is believed to have longer term ambitions for national office.

Other sceptical Republicans are looking for new jobs or struggling to keep their current ones:

l Sen. Sam Brownback of Kansas, who has White House aspirations, has asked whether the Foreign Intelligence Surveillance Act should be updated.

[bul] Sen. John McCain of Arizona, another presidential aspirant, says oversight is needed to determine if the program is legal. “Congress has to be briefed,” he said.

[bul] Sen. Mike DeWine of Ohio, struggling in his re-election battle this year, has said changes in law are necessary to give the White House the statutory authority to conduct the monitoring — and end the controversy. He is writing legislation that would exempt the program from FISA and require regular briefings for select lawmakers.

[bul] Sen. Chuck Hagel of Nebraska, a maverick who is thinking about running for the White House in 2008, called for a Senate inquiry in December, along with his colleague on the Senate Intelligence Committee, Sen. Olympia Snowe of Maine. The moderate Snowe, lacking a challenger, is a shoo-in for re-election in November and routinely breaks with the White House.

In a closed committee session on Thursday, Snowe and Hagel voted to give the White House until early March to work with Congress on legislation and further briefings.

Then, the committee may reconsider an investigation. “Senator Snowe believes we are at a starting point in terms of negotiations,” her spokeswoman said.

Polls show that approval for Bush’s US-based terrorist surveillance programme is growing. An AP-Ipsos poll last week showed that people are now evenly divided on whether the administration should be required to get warrants before monitoring domestic calls overseas.

The diminishing support in Congress is not yet a revolt, in part because terrorism remains a top concern to voters, rating third in importance, behind the war in Iraq and the economy.

The Republican Party still has many believers in the fight against terrorism as a political strategy. The Republican National Committee and Vice President Dick Cheney have made clear they intend to try to capitalise on it, and they see the NSA programme is a winning issue.

At a dinner last week, Cheney said the discussion of the NSA programme “has clarified where all of us stand”.