That's not an attack on John McCain at all, and certainly not the kind of attack Kirchick construes it as. The cartoon depicts various obstacles to McCain's political aspirations -- George Bush, Hillary Clinton, Barack Obama -- as his North Vietnamese captors. I don't find this to be a funny or successful cartoon, but surely nothing that depicts McCain's political adversaries as war criminals can seriously be considered a smear against McCain.
This article available online at:
http://www.theatlantic.com/politics/archive/2008/07/double-standards/49327/
