Rep. Bart Stupak of Michigan states that the White House and Democratic Party leaders in Congress have been pressuring him not to speak out against the "compromise" language regarding abortion in the health care bill. Stupak is one of a group of Blue Dog Democrats and is also pro-life. He was one of the leaders of the Blue Dog stand against the health care bill in the House of Representatives.
Personally, by taking a stand like this against his own party, I believe that his political career (at least, within his current party) is probably done for anyway. If you're gonna go out, then, why not go out swinging and stand by your principles?