A poll came out today showing that Olympia Snowe (R-ME) might be vulnerable to a primary challenge from the right, even though the GOP would probably lose the seat if they forced her off the ticket. Yglesias thinks she will have to switch parties:
This means that when you’re thinking about whether Snowe will support a bill or not, the issue ultimately comes down to not triggers versus non-triggers, or employer mandates versus free rider fees, but whether Snowe wants to remain a Republican or not. Based on this polling, a Snowe who votes for a comprehensive health care overhaul is basically not going to be viable as a GOP primary candidate. Conversely, a Snowe who votes for comprehensive health reform and switches parties would remain a very popular general election candidate with a safe seat.