Just what I've always wanted: a debate with presidential candidates, albeit through intermediaries:

Fortune: Jonathan Chait has written in The New Republic that if John McCain circa 2007 were running against John McCain circa 2000, he would call John McCain 2000 a Communist.

McCain: My principles and my practice and my voting record is very clear. Not only from 2000, but 1996 and 1992 and 1988 and 1986. And, you know, it's kind of a favorite tactical ploy now that opponents use, of saying the person has changed. Look, none of my principles or values have changed. Have I changed position on some specific issues because of changed circumstances? I would hope so! I would hope so! When I came back from the 2000 campaign that Mr. Chait refers to, I didn't know anything about climate change. But I'd been informed by the voters of New Hampshire that came to the town hall meetings. So I held hearings on climate change, and so I became dedicated to the proposition that we must reduce greenhouse gas emissions; otherwise we're gonna hand the next generation of Americans a more-damaged planet. Now if Mr. Chait wants to say that I've changed on climate change, fine, I'm proud of it.

(The column cited by Fortune is here.) McCain here is citing one example of an issue where he moved left since 2000. The point of the column he was asked about is that there are many more issues where he moved right since then, coinciding with his effort to secure the 2008 GOP presidential nomination.

Meanwhile, McCain is going around saying things like, "I take stands on principle, and I don't switch positions depending on what audience or what time it is in the electoral calendar." Apparently we're supposed to swallow the notion that Barack Obama's (short) list of policy reversals is entirely motivated by political calculation, while the extremely long list of issues where McCain has moved right since 2004 is a response to "changed circumstances."

--Jonathan Chait