Rep. Michele Bachmann (R-Minn.) is still weighing whether to sign a pledge backed by conservatives in Congress and most of her fellow Republican presidential hopefuls vowing to oppose any effort to raise the debt limit unless deep spending cuts and a balanced budget amendment are included as part of the deal.

Her reluctance has perplexed and irritated some conservatives, including Sen. Jim DeMint (R-S.C.), who said Wednesday he was “disappointed” that she had not joined much of the Republican Party’s conservative wing in supporting the pledge.

Last week, Bachmann said during a South Carolina town hall meeting that she felt the “Cut, Cap, Balance” pledge did not go far enough and should include a demand to repeal last year’s health-care overhaul, which she and other critics refer to as “Obamacare.”

On Thursday, her position appeared to have solidified into a no-vote under any circumstances. “I will not vote to increase the debt ceiling,” she said firmly in her first television ad, which began airing in Iowa.

Still, a spokeswoman on Thursday indicated that Bachmann may yet sign the document.

“She would like for ‘Cut, Cap and Balance’ to go a little further. She would like it to repeal Obamacare. But at this point she’s still reviewing it,” said spokeswoman Alice Stewart, adding, “We stand by the ad.”

Titled “Waterloo,” the television spot centers on the Iowa town where she was born and underscores her efforts to curb federal spending. It is airing in advance of the Aug. 13 Ames Straw Poll, which is credited with giving candidates early momentum in the first-in-the-nation caucus state.

Bachmann’s hesitancy puts her at odds with most of the other candidates seeking the GOP nomination for president, including Mitt Romney, Tim Pawlenty, Herman Cain, Newt Gingrich, Rick Santorum and Rep. Ron Paul (R-Tex.), who are among those who signed it.

On Wednesday, DeMint told CNN he was disappointed that Bachmann had not signed the pledge, and that it was not the place to include calls to repeal the health-care law.

“This is not the conservative agenda,” he said. The pledge includes “one focus we have to have, [which] is, we have to stop spending more than we’re bringing in.”

White House officials say the $14.3 trillion ceiling on the amount the federal government can borrow must be raised by Aug. 2 or the nation faces a potentially disastrous default.

The “Cut, Cap, Balance” pledge is backed by 12 GOP senators and 28 Republican members of the House. The signatories say they will not support any deal that fails to include substantial budget cuts, statutory spending caps and a constitutional amendment requiring a balanced budget.

Some Republicans, including Sen. John McCain (Ariz.) and House Majority Leader Eric Cantor (Va.), have declined to sign the pledge, saying it is not realistic and could undermine negotiations with President Obama and congressional Democrats.