The one certainty of the 2008 campaign, it might have seemed, was that Sen. John McCain would be acknowledged all around as a war hero for his service in Vietnam—but apparently not. Politico’s Josh Kraushaar notes that former Gen. Wesley Clark, now supporting Sen. Barack Obama, questioned McCain’s hero status in a Sunday appearance on CBS’s “Face the Nation.” Clark asserted: “I don’t think getting in a fighter plane and getting shot down is a qualification to become president.”

That leads Kraushaar’s Politico colleague, Ben Smith, to take a deeper look at the left’s growing willingness to question McCain’s hero status. “The highest voltage third rail of this presidential campaign may not be race, sex, or age, but Senator John McCain’s military service,” Smith writes.

Naturally, Barack Obama is going to distance himself from attacks on John McCain's military service. And, to a large degree, after seeing the Swift-Boating of John Kerry, Democrats are sensitive to unfair attacks on military service. But we're also sensitive to double standards and hypocrisy on this issue. John McCain's military record, outside of his time as a captive, is filled with behavioral problems, poor grades, crashed planes, etc. For the most part I think Democrats are willing to give John McCain a pass on this sordid history in deference to his years of suffering in Hanoi. But the problem is that we have to deal with commentary like this from the Washington Post's Richard Cohen:

McCain is a known commodity. It's not just that he's been around a long time and staked out positions antithetical to those of his Republican base. It's also -- and more important -- that we know his bottom line. As his North Vietnamese captors found out, there is only so far he will go, and then his pride or his sense of honor takes over. This -- not just his candor and nonstop verbosity on the Straight Talk Express -- is what commends him to so many journalists.

Obama might have a similar bottom line, core principles for which, in some sense, he is willing to die. If so, we don't know what they are. Nothing so far in his life approaches McCain's decision to refuse repatriation as a POW so as to deny his jailors a propaganda coup. In fact, there is scant evidence the Illinois senator takes positions that challenge his base or otherwise threaten him politically. That's why his reversal on campaign financing and his transparently false justification of it matter more than similar acts by McCain.

You can see how Cohen grants McCain a magic shield that protects him against all charges of inconsistency or hypocrisy. McCain was courageous in captivity so nothing he does now can be anything but courageous and consistent. Richard Cohen probably doesn't realize it, but it is coverage like he is providing that gives rise to comments like the one Wesley Clark made.

“I don’t think getting in a fighter plane and getting shot down is a qualification to become president.”

Of course, Cohen would argue that it isn't the getting shot down that matters. It's the fact that McCain refused an early release so that another prisoner could go home before he did. Maybe doing something like that qualifies you to be president. I think it was no more than what protocol demanded from John McCain, but at least he followed protocol. We could use a president that follows protocol. But even if we admire McCain's courage in captivity, it should not give him a magic shield against charges of hypocrisy. It doesn't make him a known quantity who is incapable of political cowardice and pandering.

If you don't set up such a ridiculous double standard, people won't feel the need to attack the double standard by questioning the validity of its premises. I don't think John McCain's military service carries much voltage outside of the underpants of the Beltway punditocracy.