I have no idea about what considerations moved Bart Stupak to announce his retirement. But I can’t help thinking that his decision not to run for reelection is a pretty significant moment in the ideological contest over ObamaCare.
The liberal wing of the Democratic Party supports both ObamaCare’s insurance reform and its indirect public subsidy for abortions; Republicans oppose both of those things. Stupak’s pro-life congressional Democrats were the only political players for whom ObamaCare presented a serious ethical dilemma because it pitted the claims of the uninsured against the claims of the unborn.
That made Stupak a central figure in the ideological battle over ObamaCare. If you take him at his word, his decision to support it in the end turned on his belief that securing everyone’s right to affordable health insurance is an ethically urgent enough imperative to compete with the claims of the unborn in the eyes of a committed pro-lifer. No other Democrat was positioned to make the case for ObamaCare's ethical urgency as credibly to people whose minds aren’t already made up.
It’s especially unfortunate for ObamaCare supporters, then, that Stupak has decided not to make it in the forum that matters most.