GOP strategist Karl Rove won't let up in his attacks on Democratic presidential hopeful Hillary Rodham Clinton, but the intriguing question is why.

From TIME:

Master GOP strategist Karl Rove won't let up in his attacks on Democratic presidential hopeful Hillary Rodham Clinton, but the intriguing question is why.

Is it a sign that Rove, who masterminded Bush's two presidential victories, is worried about Clinton? Or a calculation that the GOP attacks will get Democrats to rally to her side because the GOP would prefer not to take on Democrats John Edwards or Barack Obama?

Asked why he was helping Clinton by saying she would headline the ticket, Rove said: "Didn't know that I was. Don't think that I am."

Then he harshly criticized Clinton, saying more people have an unfavorable than favorable opinion of the New York senator and former first lady.

"She enters the general election campaign with the highest negatives of any candidate in the history of the Gallup poll," Rove said.

Rove might be revisiting his 2004 play book. Bush's re-election team aimed its harshest comments at Massachusetts Sen. John Kerry, the eventual nominee, because it wanted Bush to take on Kerry rather than Edwards, then a senator from North Carolina.

At a Democratic debate in Iowa on Sunday, Clinton responded to Rove's criticism.

"I don't think Karl Rove is going to endorse me, but I find it interesting that he's obsessed with me," she said.