Is Snowe vulnerable?

Ezra Klein looks over recent polling data suggesting 59% of Maine Republicans want to dump Olympia Snowe and opines:

Snowe isn't up for reelection until 2012. This polling shows that in 2009, at a moment of maximal heterodoxy, Snowe isn't popular among her state's Republican voters. But if she shapes up in 2011 and really nails the Obama administration? Hard to say. I can think of a lot of senators who have lost reelection in recent years. I can't think of any who lost because of a vote they cast three years before the campaign.

Maybe not reelection, but what about renomination? Joe Lieberman lost his party's nomination in 2006, arguably because of the Iraq War vote he cast in 2003. Hillary Clinton may have lost the presidential nomination in 2008 because of the same vote.

Voters, in general, have short memories. But party activists, the ones who reliably show up in primaries and raise money and volunteer their time for candidates, have extremely long memories. Three years is like three days.