Threatened by the prospect of a competitive GOP primary just 11 months from now, Sen. Olympia Snowe is using the partisan battle over the debt ceiling to paint herself as a conservative stalwart.

The moderate Maine Republican isn’t being shy about calling for greater fiscal discipline and highlighting her long-standing support for a balanced budget amendment, both of which are issues that could help her with tea party activists frustrated by her long record of bipartisanship.

Snowe penned an opinion piece for the Wall Street Journal last week promoting the constitutional amendment she coauthored with Sen. Jim DeMint (R-S.C.), a champion among tea partyers for the strong backing he lent conservatives who ran in contested primaries in 2010.

On Tuesday, Snowe followed up the opinion piece, which DeMint co-wrote, with an email fundraising appeal referencing her collaboration with DeMint and reiterating her push to enact fiscal reforms during her three terms.

The Senator disavows the notion that campaign politics have influenced her work on Capitol Hill. But during a brief interview with Roll Call, it was clear that Snowe is sensitive to suggestions that she may have changed her position on budget matters to satisfy Republican primary voters displeased with a centrist voting record that is a perfect fit for usually left-leaning Maine.

“Do you know my history? You’re all feeding into conventional wisdom. That’s the point,” Snowe said, scolding reporters. “You all just arrived here, I’ve been here, and I have a record on the balanced budget amendment, so no one should be surprised — anybody who knows me.”

Snowe added that she has supported a balanced budget amendment since she became a Member of the House in 1979.

“There’s no deviation. So no one should be surprised,” she said. “I’ve been very loyal to my traditional roots of fiscal responsibility as a Republican.”

Snowe told the Bangor Daily News she would not vote to cut Medicare or Social Security as part of a debt ceiling deal, although she declined on Tuesday to rule out anything — including a package that does not include the balanced budget amendment — until she reviews the final deal.

DeMint, who has raised millions of dollars for insurgent Senate Republican primary candidates through his Senate Conservatives Fund political action committee, said he found nothing odd about his partnership with Snowe on the balanced budget amendment. He chalked it up to the broad support fiscal restraint now enjoys among Republicans on Capitol Hill.

DeMint does not plan to get involved in 2012 primaries with GOP incumbents.

“All I’m interested in right now from all of our Members is a commitment to balance our budget. Anyone who wants to work with us — Olympia certainly has — that’s what’s important right now,” DeMint said. As for their opinion piece, he said, “That was the whole point of us doing it together, to show the full spectrum of the Republican Party realizes that we can’t get control of debt if we don’t stop spending more than we’re bringing in.”

Snowe has remained active in Maine Republican politics throughout her career and has a close relationship with Gov. Paul LePage (R), who was elected in 2010 with strong tea party support. She hasn’t faced a primary challenger in 14 consecutive elections going back to her tenure in the House, winning most of her general elections by comfortable margins.

But the Senator’s concern as 2012 approaches is well-founded. Conservative advocacy groups and tea party organizations that caused problems for establishment Republican candidates in 2010 are eyeing Snowe, with plans to get involved in her primary if a strong challenger emerges and a sizable grass-roots opposition mobilizes.

National Democrats also are recruiting in Maine, but top Democrats in the state are waiting to see if Snowe is vulnerable to an intraparty challenge, given she has a 60 percent approval rating statewide. (She had a 49 percent approval rating among Republican voters in a March poll conducted by the Democratic firm Public Policy Polling.) Maine voters must be registered with the party to vote in a primary.

Snowe’s two announced primary foes are not considered formidable, and the Senator might yet escape unscathed given her historical popularity with Maine Republicans. But the somewhat hard line Snowe is taking on the debt ceiling and her voting record — she voted with her party 69 percent during the last Congress and 85 percent during this Congress —  may not be enough to absolve the Senator in the eyes of national conservative activists.

“We’re still looking at the big picture of who this person is,” Tea Party Express spokesman Levi Russell said. Club for Growth spokesman Barney Keller said the conservative group is “continuing to look closely” at getting involved in Maine.

The National Republican Senatorial Committee is staying out of Snowe’s primary. But NRSC Chairman John Cornyn (Texas) said that Maine’s senior Senator is doing everything right to prepare for 2012, noting in particular her fundraising and work on the balanced budget amendment.

Cornyn indicated that he does not foresee a problem for Snowe in the general election, should she win her primary. Democrats might target her, given that Maine has voted Democratic in recent presidential elections, but that would depend on their ability to recruit a top-tier challenger.

“Who would have imagined you’d ever see a joint op-ed with Jim DeMint and Olympia Snowe on the balanced budget amendment? It demonstrates her sensitivity to the issues that are at the forefront of her constituents,” Cornyn said. “In her case, it’s all about the primary. That’s the wild card.”