A reader writes:

Where we diverge, I think, is in our views of last night's debate. Yes, McCain shone on the torture issue; we've come to expect that from him. And if I were more devout, I too would say "God bless him" for it. And yet I can't quite get past the cheapness and pettiness of McCain's rhetorical tactics. I refer specifically to his exchange with Paul over Iraq, to which you also objected.

Like you, I am torn between Ron Paul and John McCain as my Republican candidate of choice in the Presidential election. I would be quite proud to cast a vote for either; Paul's uncompromising dedication to true conservatism is inspiring, and McCain's personal honor, and his credibility as a leader in the struggle against Islamist repression, are appealing.

We all want to believe in John McCain. But moral credibility is a double-edged sword. As valuable a commodity as it is when employed for honorable purposes, it is all the more dangerous when employed in pursuit of ignoble ends.

In other words: when Rudy Giuliani says shallow, puerile, and dishonorable things, it bugs me, but it doesn’t SCARE me, because everybody expects that of Giuliani. We all knowhis supporters and opponents alikethat he’s a political animal and a turd of a human being, and his use of a tactic does nothing to burnish its credibility.

When John McCain employs his moral force in an unworthy rhetorical tactic, that’s another matter entirely. The tactic comes to seem less offensive because a person of McCain’s moral stature engages in it.

And that, in turn, leads me to wonder whether we can afford to have a man of McCain’s moral stature engaged in the process of Presidential politics. Because when John McCain debases himself, he debases us all. And it disappoints me far, far more than anything Rudy Giuliani could possibly do.

America needs Ron Paul, and America needs John McCain. But we need them both at their best. And time after time, it seems to me, the demands of Presidential politics have caused John McCain to stoop, and Ron Paul to elevate himself. It's increasingly hard for me to see myself rewarding John McCain for this behavior by endorsing him.