He isn't a moderate. Mr. McCain's policy positions and Senate votes don't just place him at the right end of America's political spectrum; they place him at the right wing of the REpublican Party.
And he isn't a maverick, at least not when it counts. When the cameras are rolling, Mr. McCain can sometimes be seen striking a brave pose of opposition to the White House. But when it matters, when the Bush administration's ability to do whatever it wants is at stake, Mr. McCain always toes the party line.
While I think Krugman's analysis of Arizona's senior Senator is ultimately correct I don't think this is a cat you want to let out of the bag. If McCain decides to run for President in 2008 his moderate image may prevent him from winning the nomination for lack of traditional conservative voters supporting him. I would argue that McCain cannot be beaten, he's too well liked accross party lines. Should he decide to run, the only thing keeping him out of the White House will be the Republican Primary, and in that setting his moderate image might kill him. So let's not tell the public that McCain is a right winger just yet.