WASHINGTON - How much does Republican Sen. John McCain, who promises to “reach across the aisle” should he become U.S. president, raise hackles among ultra conservatives? 

If you are Ann Coulter, who is prone to controversy-stoking tirades against those she perceives as liberal, the answer is: a lot.

Railing against the Arizona senator late on Thursday for lacking sufficiently conservative Republican credentials, Coulter said she could even be driven to back McCain’s Democratic rival Hillary Clinton.

“If he’s our candidate then Hillary’s going to be our girl … because she’s more conservative than he is,” Coulter said of the New York senator and wife of former President Bill Clinton.

“I think she’d be stronger on the war on terrorism. I absolutely believe that,” Coulter said. “I will campaign for her if it’s McCain.”

It seemed the Clinton campaign was not tripping over itself to embrace Coulter’s “endorsement.” Clinton spokesman Phil Singer did not immediately respond to a request for comment.   

Click here for more Reuters 2008 campaign coverage. 

- Photo credit: Reuters/Kevin Lamarque (Clinton and McCain at the 2007 prayer breakfast.)