After months of throwing nails in his path, Rep. Emanuel Cleaver is now climbing aboard the Obama bus.

   The Kansas City Democrat had stuck with Sen. Hillary Clinton until the bitter end. He would occasionally say things during the campaign that seemed designed purely to irritate her opponent.

   It began last summer when he endorsed Clinton on the very day that Sen. Barack Obama was in Kansas City for a speech. In his remarks, Cleaver predicted that the Illinois lawmaker would eventually be the first black president, but that it was "not his time — yet."

   The implication was that Obama was not ready.

   Another time, Cleaver tried to undercut one of Obama’s strongest selling points: his rhetoric. He said that in comparison to "a lot of other African American speakers," Obama was really just kind of so-so.

   "He may not even measure up," Cleaver said.

   He also charged that Obama supporters had "harassed and threatened" black superdelegates loyal to Clinton. Cleaver said they were attacked with "Uncle Tom" insults.

   Still, allies of the presumptive Democratic nominee had been trying to win Cleaver’s help for months without success.

   "I had dozens of conversations about his decision," said Democratic Rep. G.K. Butterfield of North Carolina, a friend. "He struggled with it for a very long time and decided to stay with his convictions."

   Butterfield said Obama understood Cleaver’s longstanding loyalties to the Clintons and did not hold a grudge.

   During the North Carolina primary campaign, he said Obama told him that he "was confident that Cleaver would be there at the end."

   Sen. Claire McCaskill of Missouri, a top Obama advisor, reached out to Cleaver on the eve of the final primaries when it seemed clear that Obama would clinch the nomination.

   "I told him that I appreciated his loyalty to Sen. Clinton, but that if Barack wrapped up the nomination, how excited we would be to have his help when the time was right," she said. "He’s been a great campaigner for other presidential candidates."

   Cleaver said he welcomed the offer.

   "She just called and said, ‘Barack is going to need you in Missouri’" and possibly elsewhere, Cleaver said.

   McCaskill said that Cleaver could help energize Clinton voters, particularly in parts of the state like Hannibal, where he appeared in March at the annual Democrat Days.

   "Normally when African Americans are asked to get involved in campaigns, they want us work the central (city) wards," Cleaver said. "But this actually is the thing that’s going to be the most helpful. The problem we have right now is trying to convince fired-up Democrats that this is not going to be a blowout."