The Progressive Change Campaign Committee, which sponsors pro-abortion candidates to challenge pro-life Democrats in primaries, is behind the effort.
"The Stupak Amendment goes farther in restricting a women’s right to choose than Republicans passed during the entire Bush presidency," the group complains.
The group sent an email to its members on Wednesday challenging them to raise $10,000 and promising to air a barrage of Internet ads attacking Stupak if they met the goal.
In under five hours, 425 contributors pledged $12,107.
The ad features a picture of a distressed young woman with the text, "Women, not sure what to do with your body? Rep. Bart Stupak will tell you."
The group also encourages abortion advocates to sign a letter sponsored by Democratic Reps. Diana DeGette of Colorado and Jan Schakowsky of Illinois to Speaker Nancy Pelosi saying they will vote against the final version of the health care bill if the Stupak amendment is not removed.
"As Members of Congress we believe that women should have access to a full range of reproductive health care. Health care reform must not be misused as an opportunity to restrict women’s access to reproductive health services," they wrote earlier this week.
They said the Stupak amendment "represents an unprecedented and unacceptable restriction on women’s ability to access the full range of reproductive health services to which they are lawfully entitled" and promised to not "vote for a conference report that contains" it.
Stupak has responded by saying they are "playing with fire" by making such threats and promising to defeat the bill if his amendment is removed.
"We won because [the Democrats] need us," says Mr. Stupak. "If they are going to summarily dismiss us by taking the pen to that language, there will be hell to pay. I don't say it as a threat, but if they double-cross us, there will be 40 people who won't vote with them the next time they need us—and that could be the final version of this bill."