SENATOR HOTHEAD…. McClatchy notices that John McCain has a temperament problem.

John McCain made a quick stop at the Capitol one day last spring to sit in on Senate negotiations on the big immigration bill, and John Cornyn was not pleased.

Cornyn, a mild-mannered Texas Republican, saw a loophole in the bill that he thought would allow felons to pursue a path to citizenship.

McCain called Cornyn’s claim “chicken-s—,” according to people familiar with the meeting, and charged that the Texan was looking for an excuse to scuttle the bill. Cornyn grimly told McCain he had a lot of nerve to suddenly show up and inject himself into the sensitive negotiations.

“F— you,” McCain told Cornyn, in front of about 40 witnesses.

It was another instance of the Republican presidential candidate losing his temper, another instance where, as POW-MIA activist Carol Hrdlicka put it, “It’s his way or no way.”

There’s a lengthy list of similar outbursts through the years: McCain pushing a woman in a wheelchair, trying to get an Arizona Republican aide fired from three different jobs, berating a young GOP activist on the night of his own 1986 Senate election and many more.

Many more, indeed. McCain has nearly came to blows with Sen. Chuck Grassley (R) of Iowa and Sen. Richard Shelby (R) of Alabama; he tried to intimidate former Sen. Bob Smith (R) of New Hampshire; and he’s screamed obscenities at Sen. Pete Domenici (R) of New Mexico and Sen. Christopher Bond (R) of Missouri. He’s even lost his cool in international settings. Sen. Thad Cochran (R) of Mississippi recently said, “The thought of him being president sends a cold chill down my spine. He is erratic. He is hotheaded. He loses his temper and he worries me.”

Sounds like the ideal candidate to lead a nation during a war, right?

Thomas De Luca, professor of political science at Fordham University in New York, put it this way: “In the nuclear age, you don’t want someone flying off the handle, so it’s a critical question: Can McCain control his temper?”

Under the circumstances, it’s hardly an unreasonable question.

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Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.