It’s about how he’s evolved from being a soi-disant straight-shooter to leading the charge against Barack Obama on both domestic and foreign-policy fronts:

For years, McCain relished being an outsider and a maverick, a style that often led to battles with his own party’s leadership. Today, for reasons that friends and McCain observers say could range from unresolved anger to concern for his right flank as he seeks re-election to genuine dismay about Obama’s agenda, he is helping lead a fiery crusade of GOP loyalists against Democratic priorities—and irked some of his Democratic colleagues in the process.

Now, of the reason’s cited, “concern for his right flank” is the telling one. McCain’s sanctimony has always been a device to further his ambition; and his much bruited-about acts of supposedly nonpartisanship concealed his dreary right-wing positions on many issues.

This New John McCain is just the most recent example of how those pretenses evaporate when it’s not politically convenient for him; his positions now—not supporting Sonia Sotomayor, attacking the AARP when it tries to help with health-case reform, sniping at the president’s decision-making process about what do to with the unholy mess the Republicans left him with in Afghanistan—are just more indications of his grimy and unattractive partisanship and self-interest.

For an in-depth and pretty unforgettable look at how this move isn’t much out of keeping with the real John McCain, see Tim Dickinson’s brutal look back at his personal history in Rolling Stone. The piece is funny, too:

In its broad strokes, McCain’s life story is oddly similar to that of the current occupant of the White House. John Sidney McCain III and George Walker Bush both represent the third generation of American dynasties. Both were born into positions of privilege against which they rebelled into mediocrity. Both developed an uncanny social intelligence that allowed them to skate by with a minimum of mental exertion. Both struggled with booze and loutish behavior. At each step, with the aid of their fathers’ powerful friends, both failed upward. And both shed their skins as Episcopalian members of the Washington elite to build political careers as self-styled, ranch-inhabiting Westerners who pray to Jesus in their wives’ evangelical churches.

In one vital respect, however, the comparison is deeply unfair to the current president: George W. Bush was a much better pilot.