Obama's poker buddies encouraged him to stand up to Hendon and Trotter, but he refused. Not his style, he said. And why sink to their level? When Hendon ridiculed Obama, his standard comeback was a dismissive shrug and a wave of his hand. Ah, Rickey, you've always got something to say."I never would have called him a fighter," Hendon said. "He used the silk gloves, and I used the iron fists."

The tension between the two men peaked on June 11, 2002, after Hendon made an impassioned speech on the Senate floor urging his colleagues to preserve funding for a child welfare facility in his district. It was, Hendon remembers, "basically the most emotional speech of my life, and I was pulling out all the stops." Every Republican still voted against him. Every Democrat voted with him -- except Obama and three other members who made up a faction known in Springfield as "liberal row."

Incensed by those four votes, Hendon walked across the floor and confronted Obama, who explained by saying "something about fiscal responsibility," Hendon recalls. A few minutes later, after Hendon's proposal had lost, Obama stood up and asked to have his previous vote changed to a "Yes" for the record, saying he had misunderstood the legislation. His request was declined, and Hendon stood to criticize Obama for political maneuvering.

Infuriated that Hendon had embarrassed him publicly on the Senate floor, Obama walked over to his rival's seat, witnesses said.

"He leaned over, put his arm on my shoulder real nice and then threatened to kick my ass," Hendon said.

The two men walked out of the chamber into a back room and shoved each other a few times before colleagues broke them apart, Hendon and other witnesses said. Obama and Hendon never talked about the incident with each other again, but they reached an awkward understanding. Hendon stopped teasing Obama; Obama started voting with Hendon more regularly. Hendon now supports Obama for president.

Some of the legislators on the floor that day believed Obama had finally snapped after more than five years of tolerating Hendon's provocations. But Obama's allies, the poker buddies and other friends who knew him best, wondered if his actions resulted from a deeper calculation. Had he actually reacted, so uncharacteristically, out of pure emotion? Or was his scuffle with Hendon a final, brilliant tactic in coalition-building?

"He finally met Rickey on his level, and that got him some respect," Lightford said. "That's what Barack needed to do, and it worked. They didn't tease him so much after that. It was like they finally realized that Barack was more than some soft punk to push around. He could play tough to get his way."