With Scott Walker out of White House race, Obama loses a favorite political foe

With Scott Walker out of the White House race, President Barack Obama is losing a favorite political foe.

For months, Obama has been challenging the Wisconsin governor on everything from his ardently anti-union positions to his shallow foreign policy experience.

Walker's advisers tried to use Obama's barbs as proof that Democrats were worried about his prospects for electoral success. And indeed, Democrats did view Walker as a potentially formidable candidate in a general election.

But Republican voters ultimately didn't feel the same way. Walker withdrew from the race Monday amid financial trouble and questions about his preparedness for the national stage.

The White House had no comment.