Rule of thumb: Celebrity entertainers damage rather than help the parties they support. Clint Eastwood just supplanted Barbra Streisand as the paradigm example. I found his performance at the Republican convention so excruciating I had to mute the TV after five or so minutes. I looked up from time to time to see if it was over. (Later I steeled myself to watch the whole thing. It's a professional obligation.) What on earth was he thinking?

And what on earth were they thinking? Talk about a blunder. Content is never king at these events: Success or failure is two-thirds stagecraft, and the Republicans had been doing pretty well, I thought. Actually, for a few moments, much better than pretty well. The testimonies from the retired firefighter and his wife and from one of Romney's former neighbors were quite something. Of course, what they said will need to be carefully fact-checked, but pending the outcome of that rigorously objective process I'd say those brief simple speeches (go to 1:38:00 in the video) were the most authentic and moving things I've ever heard emerge from an American political convention.

Deeply touching in themselves, they were also directly to the point -- who exactly is this guy Romney? They refuted the idea in which the Democrats are by now almost wholly invested, that Romney is a heartless self-serving capitalist monster.

It was GOP gold. I was thinking, rope-a-dope: How do the Democrats counter-punch this? All the convention planners had to do was follow it with Marco Rubio -- he didn't say much but he said it in a tremendously appealing way -- and then the nominee, who rose to the occasion with a pedestrian speech almost free of glitches. Instead, they gave us something else to write about. Forget the people vouching for Romney's humanity and generosity, moving the audience to tears, and telling the country something it ought to know. Let's concentrate instead on Clint Eastwood's ramblings to an empty chair. (He threw away the script, you say? Surprising! And then ran over his allotted time. By how many minutes was that? What's the state of his mental health more generally, do you know? I suppose you saw Ann Romney's expression as he spoke ... So much good stuff to discuss.)

Maybe the testimonies will make an impression anyway, but what an error to let Eastwood's squirm-inducing performance upstage them.

Rubio's quite something, by the way, isn't he. All that nonsense about the GOP's problem with Hispanics: He's most of the solution all by himself, standing right there. Like Obama, a twofer: excellent speaker, model ethnic-minority American. Yes, he'll be a hell of a presidential contender when the time comes -- and if the GOP manages what's left of the campaign the way they managed Romney's big night, he only has three years to wait.