Two years ago, Barack Obama and congressional Democrats rode a wave of voter disenchantment into power. Many Republicans, even in some traditional strongholds, were swept aside.

U.S. Sen. Susan Collins, R-Maine, was an exception. She didn’t defeat Democrat Tom Allen. She trounced him, 61-39 percent of the vote, a landslide victory political analysts attributed to Collins’ popularity with moderates, a standing shared by her Maine colleague, U.S. Sen. Olympia Snowe, also a Republican.

Two years later, the same moderate image that protected Collins from the blue wave could make Snowe vulnerable to the red one advanced by the tea party. The movement has already sacked several GOP moderates, raising questions about whether voices such as Collins’ and Snowe’s still have a place in the party.

The issue was made more prominent following U.S. Rep. Mike Castle’s recent defeat in Delaware’s GOP primary for the U.S. Senate. Castle’s loss produced strong comments from Collins and Snowe, who both found the outcome troubling.

Snowe’s reaction, described as “crestfallen” in reports by the New York Times and CNN, was particularly illuminating. The senator is up for re-election in 2012.

“We can’t be a majority party if we can’t appeal across the spectrum, if we have an exclusionary approach in general,” Snowe told the Times.

“A 100 percent ideological purity test — I don’t live in that Utopian world; it’s not reflective of the real world,” she added.

Snowe’s reaction also came on the heels of a Public Policy Polling survey that showed the majority of responding Maine Republicans would prefer a more conservative alternative in 2012. Tom Jensen, who conducted the poll, said Snowe could be in trouble if the tea party fervor extends beyond this year.

An online reader poll conducted by the Washington Post echoed that theory, showing Snowe leading the list of senators that will be targeted by the tea party next year.

All of which has given rise to speculation about Snowe’s future. Some national pundits have suggested Snowe could switch parties or run as an independent to win in 2012.

Unlike U.S. Sen. Joe Lieberman, who has changed parties once and hasn’t ruled out another second switch, Snowe’s departure from the GOP seems unlikely. Her Republican roots run deep after nearly 40 years with the party.

Snowe’s camp was reluctant to speculate about the senator’s future. However, in a written statement, the senator did address the fall of GOP moderates.

“Without 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 said.

Snowe then made a case for party unity.

“What is important for all of us as Republicans is that, regardless of differences we may have, we coalesce around those bedrock principles that have always defined the Republican Party — economic opportunity, fiscal responsibility, a strong national defense, lower taxes and a limited role for government, which my record in Congress has consistently reflected,” she wrote.

Collins said the GOP needed to be an “inclusive, welcoming party” if it wanted to win elections.

Collins said her party’s hard tack right was backlash from the Obama Administration, which she said had pursued far too liberal an agenda. Obama, she said, had also abandoned his promise of bipartisanship.

“I think the solution is more balance,” Collins said. “One-party control is bad for our country. It leads to policies that are more extreme. We need to bring President Obama back to the center. He has strayed too far to the left.”

The Obama Administration has hotly pursued Collins and Snowe on key initiatives like the health care and stimulus bills.

At one point, Snowe appeared ready to support health care when she voted for the Senate version of the bill in committee — a vote that riled hard-line Republicans. Snowe ultimately voted against the bill, calling the Obama Administration’s efforts “all windup, no pitch.”

Subsequent accounts, however, have said Snowe succumbed to relentless pressure within her party to oppose the legislation. 

Democrats have long contended that Snowe’s and Collins’ moderate images are more reputation than reality. 

“(Snowe) really has, in many ways, done what the Republican establishment wants her to do,” Michael Franz, an associate professor of government at Bowdoin College, said. “Very often she’s voting with her party.”

While both senators were openly disturbed about Castle’s defeat, they’ve since nuanced their positions to express empathy with the tea party.

Snowe, in her written statement, said she too was “angry and frustrated” with Democrats’ “regrettable policies that are creating a more invasive role for government, without appreciable or positive effect on those issues that matter most — and that is, jobs and the economy.”

Despite the speculation about Snowe’s vulnerability, not everyone is convinced a tea party challenger could defeat her.

“She’s immensely popular in this state,” Franz said.

“It’s more likely that the tea party enthusiasm could peak after this election cycle,” he added. “Movements like that, whether they’re for President Obama or something else, are somewhat hard to sustain over time.”

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