Senator Snowe, quoted by the New York Times reacting to the news that Senator Arlen Specter of Pennsylvania will switch to the Democratic Party:

Senator Olympia Snowe of Maine, who also supported the Obama administration’s economic stimulus legislation, said Mr. Specter’s decision reflected the increasingly inhospitable climate in the Republican party for moderates.

"On the national level of the Republican Party, we haven’t certainly heard warm, encouraging words about how they view moderates, either you are with us or against us," Ms. Snowe said. She said national Republican leaders were not grasping that "political diversity makes a party stronger and ultimately we are heading to having the smallest political tent in history for any political party the way things are unfolding."

Update: Politico has a bit more:

Snowe criticized party leadership for failing to change its tone after Republicans lost six Senate seats in the 2006 election.

"I happened to win with 74 percent of the vote in a blue-collar state, but no one asked me, 'How did you do it?'" she said. "Seems to me that would have been the first question that would have come from the Republican Party to find out so we could avoid further losses."