Susan Collins and Olympia Snowe Face Tea Party

Senators Collins (left) and Snowe Washington Times-Landov (left); Getty Images

Last week, Sen. Susan Collins (R-Maine) raised eyebrows in her home state by voting against the repeal of the "don't ask, don't tell" policy regarding gays in military service, a measure she championed and voted for in committee. On the Senate floor, Collins said repealing the policy was "the right thing to do" and a "vital issue," but apparently it wasn't as vital as presenting a united Republican front against a procedural matter: Senate Majority Leader Harry Reid's restriction of the number of amendments that could be attached to the bill.

Her pretzel-like position demonstrated the tightrope she and fellow Maine Republican Olympia Snowe are forced to walk in the current political environment. Northeastern moderate Republicans—fiscally frugal but socially progressive—have been an increasingly endangered species since the Sunbelt conservative takeover of the party began in the 1960s. With Tea Party sympathizers swamping Republican primaries this year, there's a question of whether moderates will soon become extinct because they lose a primary (like Delaware's Mike Castle), switch parties because they see a loss coming (like Pennsylvania's Arlen Specter), or lurch well to the right to survive a challenge (like the now unmavericky John McCain.)

"I think it's virtually impossible anymore to be a moderate in the Republican Party and survive politically," says Tom Jensen, of Raleigh, N.C.–based Public Policy Polling, which conducted a poll last month finding that Maine Republicans would favor an unnamed conservative challenger to Snowe by a 63–29 margin. "If Snowe and Collins are committed to being elected as Republicans, it is in their interests to move to the right."

Snowe and Collins are the last moderates standing, beneficiaries of Maine's longstanding love affair with centrists like former GOP senators Margaret Chase Smith (their model) and Bill Cohen (their mentor). Collins easily defeated Democratic Rep. Tom Allen to get reelected in 2008, even as Barack Obama swept 15 of the state's 16 counties. Snowe, who polls show is more popular with Maine Democrats than with Republicans, faces reelection in 2012.

In Maine, the conventional wisdom has been that both will stay in the Senate until they choose to retire, buoyed by strong support from independents, who form a plurality of the state's voters. But this year, Maine's GOP has undergone an unexpected realignment. Conservative activists organized to take over county committees, rewrite the state party platform (which now would eliminate the Federal Reserve, the Department of Education, and "efforts to create a one world government"), and throw out moderate gubernatorial candidates in favor of Paul LePage, the socially conservative manager of Marden's, a salvage and surplus retail chain.

"The Tea Party and LePage's candidacy have had a big impact on the Republican primary electorate," says University of Maine political scientist Mark Brewer. "Nobody saw this movement coming, and nobody can say for certain if it will be the dominant force two years from now when Snowe is running."

"If you polled everyone in the Tea Party movement if they liked Snowe, everyone would say no," says science fiction writer Andrew Ian Dodge, one of the Maine Tea Party movement's highest-profile activists, who found Snowe's support of Obama's stimulus package particularly onerous. "Snowe is the fly in the ointment, a Democrat with a Republican tag who is a threat to having a true Republican majority in the Senate."

"There is a mustering of the right in this state that hasn't happened in my memory, and the Tea Party movement is the flag under which people are coming together to work against progressivism, socialism, and RINO[Republican in Name Only]-ism" he adds.

In written statements, Snowe and Collins both defended the need for the GOP to remain a "big tent" if it is to stay a national force. Both offered a list of core Republican principles on which moderates and conservatives could agree, including debt reduction, lower taxes, and strong national defense. (As a practical matter, how they would simultaneously achieve all of those objectives was left unaddressed.) "Without a question there are fewer moderates now, and that is unfortunate from the perspective that moderates cannot be endangered if Republicans want to be a majority party and in a leadership position to actually implement our policies," Snowe noted, adding that she isn't currently focused on the 2012 elections.

Both emphasized areas where they agreed with Tea Party voters, with Collins stating that the movement's "emphasis on fiscal responsibility is a core Republican principle." She added, "It is great that individuals who have not previously been involved in campaigns are energized and working hard to elect candidates who are committed to bringing spending under control."

If Snowe or Collins were defeated or driven from the party, it could mark the end altogether of what was once called "Rockefeller" or "Teddy Roosevelt" Republicanism. They are the last Republican moderates left in the Northeast, the great GOP bastion of the late 19th and early 20th centuries, where frugality and government-led social reform have roots going back to the early Puritans. But even here, many moderate Republicans have abandoned the party in recent decades to become independents or Democrats, leaving a regional GOP far more conservative than the general electorate in the region.

"Our supporters are not voting in the Republican primaries anymore," says former Sen. Lincoln Chafee of Rhode Island, who lost his seat to a Democrat in 2008 after a bruising and expensive primary challenge from the right. Chafee is now running for governor as an independent. "The party's general philosophy has drifted away from traditional conservatism, where we didn't get involved in social issues, but we cared about the deficits and being sure we had clean air and water and used the tools of government to help the less fortunate and build the middle class."

Many in Maine don't believe their senators will be forced from their party but disagree on whether or not they'll trim their sails to the new political winds. "Both Collins and Snowe have represented a very blue state for a very long time and voted the way they thought people wanted," says Charlie Webster, the conservative chair of the Maine Republican Party. "They're not going to be replaced, but we need to express to them that Maine isn't as liberal as they think it is."

"Snowe has won more elections in Maine than anyone else in the 20th century, and if she decides to run again, she'll sweep the election," says Christian Potholm, a professor of government at Bowdoin College who thinks the polls on her vulnerability are "horse manure." "I don't think Snowe or Collins are vulnerable at all," he says, because of their political skills and ability to raise money. Of course, plenty of people said the same thing about Arlen Specter.