A Democratic political action committee has begun airing a devastating anti-George Allen ad in which a young girl, hitting the Republican's past Senate vote to halt funding on stem cell research, asks, "how come he gets to decide who lives and who dies? Who is he?"

But there's a problem with the attack by Majority PAC. While Allen voted in 2006 to cut funding in a bill that passed but was vetoed by former President George W. Bush, opponent Tim Kaine, as governor, in 2009 signed legislation banning the use of some state funds for embryonic stem cell research.

And he did it on a day he also approved Virginia's "Choose Life" license plates, both issues that cemented his Catholic-driven support for life.

Majority PAC of course doesn't mention Kaine's action and is unlikely to withdraw their ad since key Democrats are pushing it. It features a woman, a child and a young man who suggest they may need stem cells in the future to battle Alzheimer's, Diabetes and paralysis.

When Kaine banned funding, he was also challenging President Obama, who signed an executive order to reverse the Bush administration's ban on federal funding for research on embryonic stem cells.

The ad is part of a $7 million TV buy in critical battleground states by the group that is vying with Karl Rove's Crossroads to keep the Democrats in control of the Senate.