A 527 called BornAliveTruth.org has just released an anti-Obama attack ad that could prove troublesome for the Democratic nominee.

The spot goes after Barack Obama for having opposed the Born Alive Infant Protection Act and other similar measures during his time in the Illinois Senate. The bill mandated medical care for babies born after a failed abortion.

Certainly it sounds pretty bad -- not to mention callous -- to oppose a law like this. It's why some Republicans have accused Obama of supporting "infanticide." Of course, this being politics, that simplistic explanation may, sadly, be the one that matters most.

But the truth is that Obama was not supporting infanticide with his vote. He opposed the bill because he saw it as a back-door assault on abortion rights, and in this view he was joined by plenty of other legislators, in Illinois and elsewhere. The Chicago Tribune's Eric Zorn explains:

Illinois' liberal lawmakers needed more reassurance than federal lawmakers before agreeing to pass a "born alive" law. In part this was because abortion practice is regulated mainly by state laws, not federal laws, so seemingly benign changes in wording stand to have far-reaching consequences. And in part because the proposals were usually introduced with companion legislation that revealed a stronger intent behind the law by exposing doctors who perform mid-term abortions to additional legal risk.

So "born alive" bills failed repeatedly in Illinois from 2001 to 2004 in both chambers, with and without the involvement of then State Sen. Barack Obama.

In 2005, when additional language was added to a "born alive" bill in Illinois that explicitly spelled out that it would not impact abortion rights in any way, the law passed easily.

Proponents of the original bill, despite their constant reassurances that the proposals had nothing to do with abortion, nevertheless objected to the inclusion of the new language.

(Hat tip to Ben Smith.)

Also, as FactCheck.org says, "It is worth noting that Illinois law already provided that physicians must protect the life of a fetus when there is 'a reasonable likelihood of sustained survival of the fetus outside the womb, with or without artificial support.'"