Sure it was about immigration, Lindsey

Apparently Lindsey Graham is cracking under the immigration pressure. There have been a number of articles about the calls and letter to his office, and he even got roundly booed at his own state party convention.

So, as you read about this "heated exchange" about the immigration bill, keep in mind what's really eating Graham.

Pacing the Senate floor and waving Obama's amendment, Graham loudly accused Obama of undermining a delicate agreement whose advocates have shown political courage.

Issues that require bipartisanship often fail, Graham said, "because some people, when it comes to the tough decisions, back away." Obama's amendment, he said, would destroy the bill's prospects and bring special woe to Republicans — such as himself — who have endured conservatives' searing criticism for backing it.

It would undercut "everybody over here who's walked the plank and told our base, 'You're wrong,'" Graham said.....

Almost immediately, the two men continued the argument in a hall just outside the chamber. "They were going at it," said Sen. Mel Martinez, R-Fla. "We could hear them inside."

Why do I think that Obama might not care about Lindsey's relationship with his base?

Later: ThinkProgress has some edited video.

(While I'm doing political, Thompson might face heat on past lobbying, Giuliani takes heat for Bracewell/Giuliani's lobbying for stem cell research, and Sen. Ted Stevens has been told to "preserve records" by the FBI.)