I qualify your statement a little. He just thought he could get away with it. I suspect he is finding out that is not the case. He would not be trying to explain his actions unless he is being put under pressure by his constituents. He is just another low life politician.
Spend a few bucks supporting Stupak’s opponent, you know, just because you can (and because he IS a good pro-life conservative):
http://danbenishek.mypoliticalsite.com/