With 15 minutes’ consideration, I have to part company from my friend Bill Kristol. This was a dreadful speech — and I say this as someone who praised Hillary and Bill over the past couple of nights. The only real take-away from this speech is that he was willing to go for McCain’s throat. There was not a memorable sentence. It did not offer a new take on an old issue, or a new and exciting policy prescription. It was not elevated, or elevating; indeed, the concluding section evoking the “I have a dream” speech, on reflection, only made the speech seem mingy in tone by contrast.

It may well be that he did himself some good with Hillary Clinton Democrats and her populist, lunchbucket message. If so, it will have been effective. But it’s likely he did himself some damage as well with independent voters, who seem to make up about 11 percent of the electorate; the classic rule of thumb is that independents hate personal attacks. And while political professionals have been waiting for years for John McCain to show his legendary temper in public and damage his own career, it may have been Barack Obama who lost his cool under pressure and lashed out unwisely.

Maybe, given the decline in Republican enthusiasm and the increase in Democratic numbers, Obama can unite everyone who considers himself a Democrat this year he will have just enough to go over the top. Maybe, therefore, this will prove to have been a useful exercise for him. But showing you’re ready to get down and dirty isn’t the same as showing you’re ready to lead.

The old adage that the candidate should remain above the fray while his surrogates do the attacking will now have a pretty powerful real-world test. Republicans have an opportunity next week. Obama promises to change the tone in Washington. Maybe Republicans can change the tone in the presidential race right now. It won’t take much to do it, and actually, it’s quite natural to McCain.