Maine's Olympia Snowe has long thrived as one of the Senate's leading GOP moderates, but she has recently sided with tea partyers on high-profile votes involving Libya, the budget and the environment as she braces for a primary challenge from the right.
Such votes could help Snowe fend off tea party foes who mock her as a "RINO" — Republican In Name Only — and hope to sink her bid for a fourth term next year.
Snowe insisted she's been true to her moderate roots.
"I am who I am," Snowe said. "I haven't changed."
Another test for Snowe could come as Senate Democrats push for a vote on a GOP House budget plan that calls for deep cuts and privatizing Medicare. Democrats who see the plan as politically unpopular want to put Republicans like Snowe on the hot seat.
She backed a motion by Kentucky Sen. Rand Paul, a tea party hero, to undercut President Barack Obama's use of military force in Libya.
Snowe joined nine Republican senators, most of them conservatives, supporting Paul's motion, but it failed, 90-10. Maine GOP Sen. Susan Collins voted for it, lending Snowe political cover. Other moderates like Arizona Sen. John McCain opposed it.
Her vote was a protest against Obama's failure to consult with Congress on Libya, Snowe said.
Snowe backed Senate Republican leader Mitch McConnell's measure to ban the Environmental Protection Agency from regulating greenhouse gases. She said new regulations could hurt financially struggling manufacturers who have already made strides to curb emissions.
Snowe also voted for a Republican House budget pact that included a ban on federal money for Planned Parenthood. Snowe, a supporter of abortion rights and women's health issues, criticized the cuts before voting for the bill.
The ban was championed by conservatives who object to Planned Parenthood as the country's largest abortion provider, although federal law already bars the use of federal funds to perform most abortions.
Snowe later voted against a resolution to ban federal funding for Planned Parenthood.
New England Republicans have long survived as centrists, touting fiscal responsibility while often siding with Democrats on social issues like the environment and abortion. But Snowe has voted with her party 91 percent of the time in the new Congress, compared to just 69 percent in the previous Congress, a Washington Post voting database showed
Snowe, 64, is facing her first primary fight, after cruising to a third term in 2006 with 74 percent of the vote.
The daughter of Greek immigrants, Snowe lost her mother to cancer when she was 8. Her father died a year later from heart disease and she was raised by an aunt and uncle.
Snowe was widowed at 26 when her first husband, state Rep. Peter Snowe, died in a car crash. She won a 1973 election to fill his vacant seat. Five years later she was elected to the U.S. House where she served for 16 years before winning her Senate seat. Snowe is married to former Maine Gov. John McKernan.
She wants to avoid the fate of Republicans felled by last year's tea party surge such as former nine-term moderate Rep. Mike Castle, who was dealt a surprise defeat by tea party favorite Christine O'Donnell in Delaware's Senate primary.
"She is well aware of the fact that she's on the target list," said Castle, a Snowe ally. "She'll be ready for it."
But some tea party activists aren't buying it.
"She's trying to jump on the bandwagon," said Shelby Blakely, a leader of the Tea Party Patriots, a national group.
Andrew Ian Dodge, former Maine coordinator for the Tea Party Patriots and a freelance writer, and Scott D'Amboise, a businessman who has sought a seat in Congress before, plan primary bids against Snowe. Neither man is well-known in Maine.
"They could very easily hand that seat over to a Democrat if they aren't careful," Castle said.
Snowe has boosted her campaign account to more than $2 million to scare off challengers and has met with tea party activists across the state.
"Frankly, I share their frustration," Snowe said. "They raised some significant issues about the direction of our country."
She boasts a key tea party ally in Gov. Paul LePage, who won last fall with Snowe's backing as part of a GOP resurgence.
LePage, who counts Snowe's late husband as a mentor, has said he will back Snowe even if a more conservative challenger surfaces.
Collins said her colleague Snowe isn't taking anything for granted.
"She is not going to be surprised the way some of her colleagues were in the last election," Collins said.