Obama and Clinton are back in Washington after the primaries this week, and they're taking their superdelegate fight to the halls of Congress. Senator Clinton is meeting with Members of Congress, all of whom are also superdelegates, to plead her case. However, things don't seem to be going all that well for her:

The tide turned against Sen. Hillary Rodham Clinton (D-N.Y.) on Capitol Hill Wednesday, as even some of her supporters said she should consider ending her White House bid.

Some uncommitted Democratic superdelegates refused to meet with the beleaguered candidate when her campaign approached them in the hope of wooing them. Reps. Brad Miller (N.C.) and Lincoln Davis (Tenn.) said they were invited to meet Clinton but declined to attend.

Meanwhile, Obama is cornering his colleagues on the floor of the House:

Obama generated quite a buzz on the House floor after a morning meeting with moderate and conservative House Democrats. His fate, like Clinton’s, now seems certain to be determined by Democratic superdelegates, including many House members who have yet to declare their allegiance...

But Rep. Grace F. Napolitano , D-Calif., a staunch Clinton supporter, was decidedly cool to the unusual presence of a senator on the House floor. “I have a question in my mind whether it’s kosher, whether it’s ethical. I don’t think he should be doing this on the House floor. This is the first time I remember him being on our floor,” she said.

Rep. Elijah E. Cummings , D-Md., offered a far different interpretation. “This shows you the kind of hands-on presidency we’ll see from Barack Obama ,” Cummings said.

Obama certainly seems to be in the driver's seat at this point, and it sounds like he's hammering home his advantage. It's hard to imagine that a little hard ball will come back to hurt him; assuming he wins the nomination, no one will remember the bruised feelings of a few Clinton supporters. And it's probably not a bad idea for Members of Congress to get a direct appeal from the man who's the bettor's favorite to be the next president.