This weekend, Republicans led by Senator John McCain stepped up their withering criticism of President Obama's nominee for Defense Secretary, Chuck Hagel. In a new line of attack, Tennessee Senator Bob Corker questioned Hagel's "overall temperament." As it turns out, Corker's choice of words was more than a little ironic. After all, back in 2008 Corker and a host of other Senate Republicans with good reason said the same thing about their party's nominee for President of the United States, John McCain.

Back in 2009, Senator Corker joined his colleagues in a farewell tribute to the departing Senator Hagel. He praised Hagel as someone who exercises "tremendous independence" and "whom I have really enjoyed serving on [the] Foreign Relations [Committee]." But now that Hagel has been appointed to serve Democratic President Barack Obama, Corker's view has changed. As he explained his new doubts to George Stephanopoulos of ABC News This Week:

"Just his overall temperament and is he suited to run a department or a big agency or a big entity like the Pentagon," Corker told me. "I think there are numbers of staffers who are coming forth now just talking about the way he has dealt with them. I have, certainly questions, about a lot of things."

If that sounds familiar, it should. Five years ago, Corker expressed the same concern about Chuck Hagel's current grand inquisitor and then GOP frontrunner, John McCain. As ThinkProgress reported:

When asked by Alan Colmes whether McCain is "temperamentally suited to be President of the United States," Corker refused to say yes.

"You know, his temperamental issues have been written about," Corker said. Sometimes, McCain "says some things that I'm sure he doesn't mean, walks away, and goes, why did I say that!" Colmes remarked, "I noticed that when I asked you if he was temperamentally suited, you didn't automatically say yes." Corker avoided the issue by saying, "Well I think he is an American hero."

Corker acknowledged in the interview that he's "had his moments" with McCain.

As it turns out, so have many of Corker's Republican Senate colleagues.

Take, for example, the GOP's number two man in the Senate, John Cornyn (R-TX).

On Friday, Cornyn penned an op-ed for CNN opposing Chuck Hagel's nomination. But in March 2008, the former Giuliani supporter compared his grudging endorsement of John McCain to the death in the family:

"I sort of liken it to a grieving process. You come to acceptance," said U.S. Sen. John Cornyn, R-Texas, ticking off the conventionally accepted stages of mourning.

Cornyn had good reason. In March 2007 he was on the receiving end of a McCain tantrum. Clashing over immigration policy, McCain dropped the F-bomb on Cornyn and called his opposition "chickens**t":

"F**k you! I know more about this than anyone else in the room."

Cornyn was not alone among Senate Republicans in feeling the wrath of McCain.

On one occasion, , he blasted the mild mannered Chuck Grassley (R-IA), " I'm calling you a f****** jerk." In 1999, McCain told the Finance Committee Chairman Pete Domenici (R-NM), "Only an a****** would put together a budget like this." As Evan Thomas recounted in Newsweek in 2000:

The Republican senator witnessing the scene had considered supporting McCain for president, but changed his mind. "I decided," the senator told NEWSWEEK, "I didn't want this guy anywhere near a trigger."

(For more background on these and other McCain tirades towards his GOP allies, see the February 2008 Mitt Romney campaign memo, "The McCain Way: Attack Republicans.")

Mississippi Republican Thad Cochran, who nonetheless eventually endorsed McCain in 2008, had similar concerns about a President McCain with his finger on the nuclear button:

"The thought of his being President sends a cold chill down my spine. He is erratic. He is hotheaded. He loses his temper, and he worries me."

But now that a Democrat is in the White House, Senate Republicans like Bob Corker are projecting their fears onto John McCain's former friend, Chuck Hagel. As for the temperamental John McCain, he like many of his fellow Republicans was for Hagel before he was against him. Speaking in 2006 of his own looming presidential run, McCain said of Hagel:

"I'd be honored to have Chuck with me in any capacity. He'd make a great secretary of state."