I was surprised by how much nostalgia the lip-biting, finger-pointing Bill Clinton evoked last night. It wasn’t a pleasant feeling: I had forgotten just how much I disliked his malign charisma. But there’s no denying his talent — a natural talent that matches Reagan’s, honed not only by experience but by a discipline and will to succeed that’s simply leagues apart from anything we saw at the Republican convention last week. He set high expectations for Obama tonight, maybe too high.

What came through as much as Clinton’s perfect political technique was his sheer joy at being on stage — the national stage once more. The life of an ex-president isn’t one to envy, despite its comforts: you leave office and know you can never return to the heights you’ve just occupied, and for the next 20 or 30 years you’re a living ghost, maybe honored, certainly humored, but without any meaningful role in the republic, which is near to hell for any politician. There’s a reason so many congressmen and senators remain in office long after they’re ripe. But lower officials can turn to second careers as retainers of military-industrial firms or as celebrity professors or chancellors. An ex-president can do a little of that, but not much, and it’s hollow. Jimmy Carter, of course, has reinvented himself in retirement as Gandhi. For Clinton, a future as Elvis in Vegas would seem more plausible. (There was a certain poignancy to the Fleetwood Mac lyrics as he came onto the stage: “Yesterday’s gone, yesterday’s gone.”)

But instead he still gets to play the old role every four years, and he never played it better than last night, when for 50 minutes he was party leader and president, and Bill Clinton, again. And unlike his last few appearances, this was a chance to save a sitting president while outclassing him at the bully pulpit.

What ambitious pols of all stripes should take from Clinton’s talk is that if you want to be president, sound presidential. Clinton presented himself as everyone’s friend and leader, not an aspiring MSNBC host, the way the Republicans seemed to be auditioning for Fox. Clinton praised, effusively, Dwight Eisenhower and what he perceives as the now extinct Eisenhower breed of Republican. He didn’t go after Goldwater Republicans — his wife was one, once — but after his speech, as state delegations cast their votes for Obama, Goldwater’s granddaughter Ceci spoke for Arizona. The Democrats, and Clinton especially, know political judo: they can turn reasonableness into a deadly weapon.

Needless to say, the inclusivity did not extend to antiabortion Democrats — or antiwar Democrats, for that matter. But Clinton made the Democratic Party sound like the party of all Americans, except for the obstructionist misfits who obstinately cling to Mitt Romney and his party. Achieving this breadth of rhetorical representation, phony though it may be, is what a president does.