Sen. Barack Obama (Ill.), seeking to wrap up the Democratic presidential nomination, made a surprise visit Thursday morning to what can be called the last major battleground of the long-fought primary campaign: the U.S. House.

After a morning meeting at the UPS town house on Capitol Hill with about 20 Blue Dog Democrats, including eight who have yet to declare their support for either candidate, Obama made the walk with the lawmakers up New Jersey Avenue and onto the House floor.

He spent about 30 minutes there receiving an enthusiastic greeting from Members of Congress. He then greeted Congressional pages crowded on the steps off the House floor and posed for pictures before leading a media scrum across the Capitol to the Senate side.

Obama said he was here to “give an update not only to my supporters, but also those who are still trying to figure out” whom to endorse.

Rep. Artur Davis (D-Ala.), one of Obama’s top cheerleaders in the House, said Democratic lawmakers have concluded the nomination is all but clinched after the Senator’s decisive win Tuesday in North Carolina and closer-than-expected loss in Indiana.

“Every member of the Caucus recognizes he’s going to be the nominee of our party,” Davis said.

Davis added that he thinks lawmakers committed to Sen. Hillary Rodham Clinton (N.Y.), Obama’s rival for the Democratic nod, are ready to rally around him. “Sen. Obama came out front in a very thrilling race. So there’s appreciation and respect for him.”

While Obama seems assured of claiming the lead in pledged delegates leading up to the party’s August convention, Obama and Clinton are now largely dueling for superdelegates — many of whom are House Members — who appear poised to decide the nomination.

Rep. Debbie Wasserman Schultz (D-Fla.), a strong Clinton backer, continued to put on a brave face.

“I’m optimistic and resolute,” she said with a beaming smile.

Schultz, meanwhile, said she used to think having a joint Obama-Clinton ticket would not work, but is now a strong backer of the idea.

“That’s an unstoppable ticket,” she said. “It’s the best combination of experience and looking to the future.”