Well, DUH.

MSNBC points out the obvious….

 But many analysts believe that if Obama completes his march to the Oval Office, this backing will dissipate the first time he presses Europe to send more troops to Afghanistan or to support an aggressive U.S. military stance at odds with Europe’s strong preference for diplomacy over cruise missiles.

…

“I think some Europeans don’t understand that what plays well here may not be playing well at home,” said Anand Menon, director of the European Research Institute at the University of Birmingham in England. “The slogan, ‘Barack Obama, the guy the foreigners like’ is not necessarily a vote winner in the United States.”