Is it a sign that Rove, who masterminded President George W. Bush's two presidential victories, is worried about Clinton? Or a calculation that the Repuplican attacks will get Democrats to rally to her side because the party would prefer not to take on Democrats John Edwards or Barack Obama?
"The Democrats are going to choose a nominee. I believe it's going to be her," Bush's departing political adviser said Sunday, noting her negative rating with the public is very high.
He appeared on three Sunday talk shows after announcing last week he was leaving the White House at the end of the month to spend more time with his family.
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.
"It just says people have made an opinion about her. It's hard to change opinions once you've been a high-profile person in the public eye, as she has for 16 or 17 years." In a USA Today-Gallup poll this month, 49 percent viewed Clinton unfavorably compared to 35 percent unfavorable for Obama and 34 percent for Edwards.
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.
The Los Angeles Times on Sunday reported that Bush's former pollster and strategist Matthew Dowd said at a 2004 Harvard University conference that Bush's re-election team went after Kerry because they were more afraid of Edwards.
Asked whether he was attacking Clinton because the Republicans feared Obama, Rove replied: "I read that in the LA Times this morning. Those, those guys out in LA have got to get clued in. I mean, come on."
Asked for his opinions on Obama, Rove demurred.
"I've said enough," he said.
Rove said his party's chances in 2008 may be helped by the high negative ratings for Clinton and for the Democratic-led Congress. Congress' approval in an Associated Press-Ipsos poll this month stood at 25 percent, compared with 35 percent for Bush.
After Rove announced he was leaving the White House, he had traveled with Bush to his Texas ranch Monday, then left Friday after a barbecue for more than 300 big donors from around the United States.
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.
She said no candidate will escape the "Republican attack machine," and added: "I know how to beat them."
Last week, Clinton's campaign ran a television ad saying struggling families and U.S. troops are "invisible" to Bush. White House deputy press secretary Dana Perino called that "unconscionable." Rove said that was laughable.
On other issues, Rove:
-Blamed congressional Democrats for standing in the way of changing Social Security retirement benefit and immigration law, two important pieces of Bush's second-term domestic policy that fizzled. Democratic leaders did not want to give Bush a "political victory," Rove said.
-Said he does not think he owes an apology to Valerie Plame, whose CIA employment was revealed by newspaper columnist Robert Novak's in 2003, shortly after her husband, former Ambassador Joseph Wilson, began criticizing the administration's march to war in Iraq. Rove said he talked to Novak about Plame, but said he did not confirm that she worked for the CIA - only that he, too, had heard that she did.
-Admitted that the Republican Party is suffering. "Is the Republican Party a little bit behind the curve? You bet," he said.
Rove appeared on "Fox News Sunday," NBC's "Meet the Press" and CBS' "Face the Nation."