Moderate Republicans may be a vanishing breed elsewhere, but Maine Sens. Olympia Snowe and Susan Collins are thriving.

In a narrowly divided Senate, the two women who are willing to buck their conservative GOP colleagues enjoy outsized influence. Democrats see the pair as potential swing votes as they press forward with their health reform plan. Their support could provide a veneer of bipartisanship.

As usual, Snowe and Collins are seeking middle ground in the health care fight, working with other centrists.

Snowe is the only Senate Republican to vote for Democratic health care legislation.

Collins wants to curb health care costs. She was front and center helping Democrats pass President Barack Obama's economic stimulus plan, but only after working to scale back costs.

In a national GOP ruled by Southern and Western conservatives, Snowe and Collins stand out. Along with retiring New Hampshire Sen. Judd Gregg, they are the only New England Republicans left in Congress.

The ranks of Northeast Republicans have thinned since the 1960s when social conservatives overtook the party's more moderate Eastern establishment, so-called Rockefeller Republicans.

The point was driven home recently in upstate New York where a moderate GOP nominee dropped out of a special House race after prominent conservatives backed her Conservative Party rival. It underscored the bitter GOP fight _ often pitting the party's energized conservative base against its leaders _ over whether there's room for moderates in the party.

Some conservatives mock Snowe and Collins as "RINOS" _ Republicans in Name Only.

"We want Olympia Snowe in the big tent, but she can't say she's a Republican and then vote against the Republican position much of the time," Minnesota Gov. Tim Pawlenty, a potential presidential candidate, said in a recent MSNBC interview. He later backtracked, saying Snowe was welcome in the party.

Yet independence is what makes Snowe and Collins popular back home, where pragmatism tends to trump partisanship.

"Pragmatic best describes the typical Maine voter," said University of Maine political science professor Mark Brewer. "They may identify with a party, but they're not going to go to the mat for their party."

Snowe swept to a third term in 2006 with 74 percent of the vote.

"There's very little chance of her being challenged in a meaningful way," said Brewer. "She's untouchable."

During a tough year for Republicans nationwide, Collins glided to re-election in 2008 in a state Obama won handily. She trounced a well-known and well-funded challenger, former Democratic congressman Tom Allen.