And so it will be the job, the obligation, the solemn task of the next president to restore that trust. John McCain could do it. He's an honorable man who has fudged and ducked and swallowed the truth on occasion—about the acceptability of the Confederate flag, for instance—but always, I think, for understandable although not necessarily admirable reasons.
To be simplistic about this, you're looking here at a press that's hopelessly in the tank for John McCain. To try to be a bit more charitable, you're looking here at a press that's hopelessly invested in the doomed epistemology of character. We can't know what lurks in the hearts of pols, but we can make inferences based on their behavior. But all politicians' behavior is mixed. So we (and by "we" here I mean "Richard Cohen") read that behavior through our preexisting beliefs about their character. And since we "know" that McCain is honorable, he fudges and ducks and swallows etc. for "understandable" reasons, whereas other, lesser politicians are just soulless scumbags. Of course McCain's reasons are understandable -- he wants to win! -- but they're just the same reasons everyone else has. They pander, he's understandable. They lie, he fudges. It's all senseless.
Which is, I suppose, just another way of observing that we're looking at a press corps that's hopelessly in the tank for John McCain.