KERRY'S LIBERAL APPEAL. It's 5:30 p.m. as I finish this. In just a little less than six hours, John Kerry will deliver his acceptance speech - the proverbial most-important-speech-of-his-life, and one that will go a long way toward determining whether he can defeat George W. Bush this fall.

My Phoenix colleague Kristen Lombardi and I have stopped by a WiFi-enabled Starbucks after spending a good part of the afternoon in Cambridge with the Campaign for America's Future - an umbrella group that brings together various lefty and progressive causes and organizations. Al Gore was a no-show. His former top campaign strategist, Donna Brazile, had still not arrived by the time we had to leave. So the highlight turned out to be the Reverend Jesse Jackson, who delivered a rambling but occasionally moving speech. (You'll be able to read Lombardi's account here once she's done with it.)

One thing I want to address in these final hours of the convention is the notion that John Kerry is nothing but a centrist weenie, and that the left will have to push him continually if he's elected president. Jackson said as much today, telling the throng, "When Kerry wins, the anti-war movement will just have to get bigger the next day."

Texas populist Jim Hightower, at last Sunday's tribute to the late senator Paul Wellstone, got at much the same thing. Speaking of Kerry, Hightower said, "I don't care if he's a sack of cement, we're going to carry him to victory" - and, afterwards, be "in their face" to get Kerry and John Edwards to toe the line.

What spurs a lot of this talk, of course, is the experience with Bill Clinton. But Clinton really was a centrist with a lot of conservative impulses. Kerry is not the most liberal member of the Senate (click here to find out why), but he is an actual living, breathing liberal. As David Corn explained (sub. req.) recently in the Nation:

Kerry did support NAFTA, and he has proposed corporate tax cuts to spur investments. He once raised questions about the political costs of affirmative action (while still backing such programs). He's not a Wellstone Democrat. But compare Kerry with Bill Clinton, who still captivates the Democratic faithful. When Clinton ran for President, he burnished his centrist credentials by pushing welfare "reform" and advocating highly punitive crime legislation. This year, Kerry's post-primary lurch to the center entails cooling down the populist rhetoric (which he borrowed from his Democratic rivals) and emphasizing his "values." He has done nothing as crass as when Clinton left the campaign trail in 1992 to return to Arkansas for the execution of a mentally disabled convict. Kerry, a former prosecutor, opposes capital punishment.

Outside the Wellstone service Sunday at the Old West Church, Corn told me, "Progressives are going to vote for Kerry. Bush energizes the base enough that he doesn't have to worry about that." Corn's analogy is the Republican Party's extreme right wing in 2000, which swallowed its doubts about Bush's moderate rhetoric out of a burning desire to recapture the White House. (Of course, few knew that Bush would actually govern from the extreme right.)

Corn added of Kerry: "He is not a DLC Democrat," referring to the Democratic Leadership Council, a centrist faction that Clinton once headed. "I don't think progressives have to swallow too hard to see the positive aspects of a Kerry candidacy," Corn said.

We all know how maddening Kerry can be - the nuances, the grays, the reluctance to take a clear stand and to stick with it. But when it comes to broad themes, Kerry is a true liberal - the first to win his party's nomination since Walter Mondale in 1984, if you subscribe, as I do, to the theory that Michael Dukakis in 1988 was more of a proto-New Democrat.

There's been a lot of talk this week that the American people are much more liberal than is generally thought. "Most Americans in their hearts are liberal and progressive," filmmaker Michael Moore told the Campaign for America's Future crowd on Tuesday.

Tonight, Kerry has a magnificent opportunity to bring those liberals back into the fold - to appeal to them not as a centrist looking for liberal votes, but as a liberal who is able to explain himself in mainstream, centrist terms.