ST. LOUIS (KMOX) - She may not be attending the Democratic National Convention in Charlotte, and isn’t serving on Barack Obama’s national campaign team like she did in 2008— but Missouri Senator Claire McCaskill says that doesn’t mean she’s trying to distance herself from the president.

“I support the President. And if the President were here—which I’ve asked him to come and help me campaign — he’d say she is a great Senator, but she can be a real pain in the you-know-what, ” Sen. McCaskill said Saturday, while campaigning in St. Louis.

McCaskill said she’s capable of great independence and has occasionally butted heads with Mister Obama during their careers in Washington, but that doesn’t mean she disapproves of the job he’s done.

McCaskill faces no serious opposition in the Democratic primary for U.S. Senate.

Three Republicans (John Brunner, Sarah Steelman, and Todd Akin) are campaigning for the chance to face her in November.