On a chilly January morning in Erie, Pa., members of the anti-abortion group Susan B. Anthony List stood outside Rep. Kathy Dahlkemper's office to thank her for opposing a health care bill that didn't include stringent abortion restrictions. Ten months later, Dahlkemper and other anti-abortion Democrats are at risk of becoming an endangered species in the House.

She and others eventually signed on to the health reform law, endorsing an executive order that barred federal funding of abortions. But SBA List and other anti-abortion groups opposed the executive order, contending it was too weak.

Now, SBA List is engaged in a multimillion-dollar attack on its former allies, replete with bus tours and billboards alleging that members "voted for taxpayer-funded abortion." The group invested $1.5 million in its "Votes Have Consequences" bus tour in August, targeting anti-abortion Democrats who supported health reform. Just last week, SBA List spent $55,000 on 32 billboards dotting the districts of three vulnerable Democrats.

On the other hand, Democrats for Life of America, the group most fiercely devoted to defending anti-abortion Democrats, has been essentially inactive this election cycle. Its political action committee brought in $2,431 and spent a paltry $308, according to Federal Election Commission filings. DFLA has made no contributions to federal candidates.