Gary Hart and Joe Biden are out, done in by "character" it seems. But these are not simply two random examples of flawed characters being discovered and discarded in the course of a campaign. The deeper question is: how did two such characters rise to the top of Democratic Party politics to become presidential candidates in the first place?

There is more here than the isolated story of politicians caught in the act of self-revelation. This is a story about a certain subculture in the Democratic Party. These two fallen politicians are connected by a man and an idea. The man is pollster Patrick Caddell. The idea is generational politics.

Caddell came up with the idea of the generational candidate in 1983, then searched for a vessel into which to pour it. His first choice was Joe Biden, but Biden declined the honor. Caddell then signed on with Gary Hart, who sounded the generational theme and went a long way with it. This time around, Caddell came back to Biden. Biden obliged. The rest you know.

As for the idea, rarely has there been one as empty as generational politics. At one level it is an appeal based nakedly on age. It says: "Elect me, I'm young." But an aging population is not necessarily going to buy that. Some might even be offended by it. So generational politicians generally deny that what they offer is mere youth.

Biden, for example, shaped the idea to mean: "Elect me because I've been through the '60s, so I'm an idealist, and what we need is a return to idealism." To have lived through the '60s is perhaps an achievement, but it is hardly a credential for the presidency. Nor does it give content, idealist or not, to one's politics. Those who were "active" in the '60s (Biden, by the way, was not) have scattered politically: some are liberals, some are neo-conservatives, some have taken up environmentalism and pacifism, some have wandered out of politics altogether.

If you dig deep enough into the idea of generational politics to find out what it means -- indeed, to find out if it means anything at all -- you will finally strike something solid: the bust of John Kennedy. Generational politics is not a grand theory of historical cycles in American politics. It is not a manifesto of the political avant-garde. It is not even a form of political self-expression for a younger generation of Americans. It is a transparent and cynical invocation of the Kennedy mystique by politicians who have no idea who they are or what their party is about.

It is fitting that "generational politics" should now be a code word for Kennedy imitation because John Kennedy may be the modern father of the idea. His '60 campaign was frankly generational. After Eisenhowerian sclerosis, went the pitch, try youthful vitality. It worked. In his inaugural address Kennedy triumphantly declared that "the torch has been passed to a new generation of Americans -- born in this century . . . " as if having had a later birth date was a distinction. Never mind that the generation born in this century proceeded to give us the Bay of Pigs, the Berlin Wall, the Cuban Missile Crisis and Vietnam. It had a certain style.

After Kennedy's martyrdom, all we remember is the style, a style to be coveted and copied. Gary Hart's internalization of the Kennedy persona, down to his mimicry of the physical mannerisms, was uncanny and scary. Biden's mimicry was more cerebral. He appropriated the Kennedy brothers' thoughts, language and, so he thought as he wound himself in their rhetoric, passion.

It is no accident that of all the Democratic candidates, the two to be disqualified for having so little command of their own character -- for having no there there -- are the two who consented to play one man's vehicle (Caddell) and another man's ghost (Kennedy). Biden once said, "Sometimes I don't know where Pat Caddell ends and Joe Biden begins." A man with boundary problems of that sort would naturally have great trouble figuring where more substantial men than Caddell -- Neil Kinnock and Hubert Humphrey, for example -- end and Joe Biden begins.

On the day Biden withdrew, his Iowa campaign manager mourned the loss. Biden had so much to offer the country, said young David Wilhelm. Like what? "His campaign, his message was important to all of us. He talked about a return to idealism, getting this country moving again." The irony was perfect. Here was a Biden acolyte passing off Kennedy's 1960 theme as his boss's own. What is appalling is not that the young man might have thought he was saying something original, but that he might have thought he was saying something important.