Pittsburgh ? Presidential candidates are granted few new starts in a political season. John F. Kerry used one in Pittsburgh this week, and he chose a new face for the new season in the campaign.

The new face belongs to Sen. John Edwards of North Carolina, and the combination of the new face and an old Kerry line, trotted out for the occasion, tells us a lot about where the Democratic campaign is going this year.

First, the face. Edwards is a political phenom, greener than John Kennedy when he ran for president in 1960, equally ambitious, the sort of fellow who projects friendliness and purpose and the suspicion that there is steel beneath the velvet.

He went to Washington six years ago determined to make a difference and to make a presidential run, and the instructive thing about Kerry’s selection is that in choosing Edwards, he did what the pros begged Vice President Al Gore to do four years ago: Add some sizzle to a snoozy candidacy. (Instead, Gore chose Sen. Joseph I. Lieberman of Connecticut.) One other thing: The Republicans are sure to remember, even if the Democrats forget, that Sen. Edward M. Kennedy’s true protege in the Senate is not Kerry. It is Edwards. You’ll hear more about that later.

The Republicans have already begun their assault on Edwards — the Democrats’ assault on Vice President Dick Cheney hasn’t ceased since Election Day, so fair’s fair — and before long he’ll be described as the head of the trial-bar wing of the Democratic Party. This will not be meant as a compliment. The first volley came from the editorial page of The Wall Street Journal: “a ticket composed of a rich trial lawyer and a rich senator who married the Heinz fortune.”

This is important not because it is true (and every word of it is), or relevant (and maybe not a word of it is), but because nobody but a handful of columnists and pockets of people in the Carolinas, Iowa and New Hampshire know a thing about the new man on top of the wedding cake. Indeed, the University of Pennsylvania’s National Annenberg Election Survey shows that half the public has no clear view of Edwards.

The Democrats speak easily of a new partnership between the two men on the ticket and, later, in the White House, but that’s become a familiar chestnut on the campaign trail. You heard it first with Walter F. Mondale (who truly did pioneer a new role for the vice presidency under Jimmy Carter), and then you heard it from George H.W. Bush (remember the commission on deregulation?) and from Gore (remember reinventing government?) and then again from Cheney (whose role on Sept. 11, 2001, is only now becoming clear).

In truth, the vice president’s role remains that of best supporting actor, a lot like Prince Albert’s in Queen Victoria’s time, whose job was to look handsome and to hold the blotting paper after Victoria signed her morning orders.

Even so, the two vice-presidential nominees will hold their own debate, which is kind of like the Canadian Football League’s Grey Cup: mildly interesting as a spectacle but ultimately only a curiosity.

That will be Edwards’ best opportunity to thwart the GOP’s nascent effort to paint him as one of the rival party’s pessimists (Cheney is not exactly Mr. Fun). But it’s also the Republicans’ best opportunity to draw a contrast between their No. 2 (former White House chief of staff, former secretary of defense, member of the House for a period longer than Edwards was in the Senate) and the Democrats’ (in the Capitol for about 15 minutes, long enough to win minor fame). Bet on this: Neither the former trial lawyer nor the former Halliburton chief is likely to linger on the enduring lessons of his career in the private sector.

The biggest question about Edwards is his identity as a Southerner. The Democrats are saying he’ll help them win a few states in the South; my bet is that not one of the 11 states of the Old Confederacy will end up shaded blue on Election Night. But there’s another aspect to this: Does the presence of a Southerner take the elitist edge off the Democratic ticket? Even more than Southerners, Northerners are transfixed by (a horribly dated and hopelessly romantic) mystique about the South. If Edwards’ bourbon-smooth baritone wins Kerry a few votes in Ohio, he’ll be regarded as providing good value.

Now to the most surprising element of that unveiling in Pittsburgh’s Market Square a few days ago, besides of course the cameo appearance of former Steelers star Franco Harris, recruited no doubt to make the event seem like an immaculate reception. Kerry trotted out a great, if shopworn, evocative line, complete with telling aside, that encapsulates his entire campaign strategy. Here it is: “We may be older and grayer now, those of us who served, but we still know how to fight for our country.”

Political lines don’t get better than that one. The older and grayer is intended to project age, experience and gravity. The those of us who served is the world’s most obvious dig at a president who was in the reserves and a vice president who collected deferments during Vietnam. And the fight for our country serves double duty, as it were, suggesting that the Democrats are fighting to win back the nation from the corporate interests who have seized it even as it suggests that there are more ways to fight for American values than by sending kids to Baghdad.

Something old, something new. A whole lot of things borrowed, all in the hope of painting one more state than in 2000 blue.

David Shribman is a columnist for Universal Press Syndicate.