McCain is demonstrating his greatest weaknesses he lacks the discipline to hold his tongue and he’s too thin-skinned (sounds like Huckabee, doesn’t it?):

Sen. John McCain (Ariz.) took a swipe Tuesday at GOP senators who have criticized him during the presidential campaign, saying they “are not the most respected members of the United States Senate.”
McCain, who is the front-runner for the Republican presidential nomination heading into the Super Tuesday primaries, was referring to comments made by five-term Mississippi Sen. Thad Cochran and former Sen. Rick Santorum (Pa.).
“The thought of his being president sends a cold chill down my spine,” Cochran had told The Boston Globe after his endorsement of McCain’s main rival, former Massachusetts Gov. Mitt Romney. “He is erratic. He is hotheaded. He loses his temper and he worries me.”

Sounds like he nailed McCain, doesn’t it?
(via)