[Republicans] know exactly what they're fighting for. The Democrats do not. However the various constituencies within the Republican Party might differ, they are unified around a central idea, which can be expressed in both positive and negative language: that they are the conservators of liberty and morality, and that liberals are sending the country to hell in overdrive. Whatever Republicans do or don't believe, they believe in those two hypotheses. This unity gives them their passion.

Democrats have no such unity. they are pretty well united around a negative expression of their identity: the belief that the right wing is dangerous. But they lack a cohesive positive idea about what they're here to do. In some ways, Democrats have never had such unity. The Democratic Party of Franklin Roosevelt, for instance, took in at once both blacks and the country's most vile segregationists. But those iterations of the party -- Roosevelt's, and his successors up through Lyndon Johnson -- could at least claim unity around the idea of government using the tools of social science to solve social problems. (By the way, it's no accident that when they had an ideological unity, Democrats also were much tougher partisans, with obstreperous shit-kickers such as Johnson and Hubert Humphrey and lesser-known though important figures, among them Adolf A. Berle, whose classic book, The Modern Corporation and Private Property, today's Democrats would do well to seek out.

But now the party is split into two distinct camps on the question of the utility of government. It's not the same party that it was 60 or even 30 years ago. Its class composition has shifted dramatically. With deindustrialization, a weakened labor movement and a stronger professional middle class, the power relationships among the party's constituencies have changed. The Democrats have become a more corporate party, too, as a consequence of our campaign-finance system. And the clash of interests between its core voting bloc and its donor base is chronic and not easily reconcilable. (Recall Daschle's refusal to take up stock-option reform, a popular cause, which he delayed chiefly because of pressure from the party's high-tech contributors.)

Thus do the contemporary divisions within the Democratic Party reflect a problem that is historically unique: When Democrats can no longer agree on the central proposition that informed their conduct for the better part of a century, there really is nothing left except an amalgam of interest groups, with different agendas and disparate passions. This makes it easy enough for the other side to construct arguments built around the indictment that the Democratic Party doesn't really represent "America," but instead represents these and those distinct groups of Americans.

In this light, it makes perfect sense that there is one, and really only one, circumstance under which Democrats truly do play hardball: the nomination of federal judges. This happens because most of the Democrats' key interest groups -- women, blacks, labor and even liberal business elements -- can find common ground in opposing a judicial nominee whose ideology stings all of them. Here and only here do the party's sundry passions unite. When it came to Clarence Thomas, Robert Bork or recently defeated circuit court judge nominee Charles Pickering -- against whom Democratic senators used rhetoric of a sort they rarely employ in other situations -- the Democrats function with a single, passionately partisan voice.

But aside from judicial battles, the Democrats don't have much fight in them. . .