There's as much evidence that Sarah Palin's map of "targeted" House districts inspired the Arizona shooter as there is that the killer was inspired by Joe Manchin's "shoot the cap-and-trade bill" ad. That is to say: None. Manchin shouldn't need to explain his ad any more than Palin needs to explain her map, but for what it's worth, here's the West Virginia senator's defense:

In a statement to RealClearPolitics, Manchin, who served as West Virginia's governor for six years before winning a special election to take over the seat once held by former Sen. Robert Byrd, defended his record and the ad itself. "I've spent my whole career bringing people together, avoiding the rancor of partisan politics, and that will continue to be the focus of my work as U.S. Senator going forward," Manchin said in the statement. "The act of a deranged madman who commits a horrific act should not and cannot be confused with a metaphor about a piece of legislation." In a conference call with reporters on Monday, however, he said he likely wouldn't release the ad today. "I can't say that we would, I really can't," Manchin said. "Because it's a much more more sensitive thing we're dealing with right now."