American liberals used to promote grandiose plans to eliminate poverty, manage the economy, enhance education, and in other ways usher in a social utopia. Now, their key issue is sex.

Democrats used to be the party of blue-collar workers, farmers, and minorities. Now, many are still Democrats, but the party agenda is controlled by abortionists, homosexual activists, and Larry Flynt-along with the social elite that promotes these "lifestyle issues" in the entertainment industry, academia, and the media.

As Roberto Rivera of Prison Fellowship points out, "The dirty, not-so-little, not-so-secret of American politics is that sex long ago replaced the plight of working people as the animating principal in American liberalism." Writing in Summa Nonsensica, a briefing paper for Chuck Colson's organization, Mr. Rivera describes how, as a Hispanic city dweller concerned about civil rights and the poor, he used to be a liberal Democrat. But now, he feels betrayed. "The party stopped being the champion of the working man and became the champion of what is best called 'lifestyle liberalism.' Passion once directed toward bettering the welfare of working people is now spent on preserving the right to sexual gratification and personal autonomy."

The liberal Democrats who once waged a "war on poverty" with armies of social workers and unlimited tax dollars now assent to limits on welfare programs. Keynesian economics, in which the government purportedly manages the economy through deficit spending, has become passé, in favor of the free market. Democrats are still bankrolled by the unions, but many defy their interests by voting enthusiastically for NAFTA and the global economy.

In post-Reagan America, conservatives have won most of their arguments. But in apparently conceding the validity of conservative economics, liberals have dug in to defend the one legacy of the '60s many really care about: "free love."

Behind their fanatical commitment to abortion-which does not even draw the line at the atrocity of partial-birth infanticide-is the compulsion to disconnect sex from having children. Sex is to be for pleasure alone, not for making families.

And if sex is merely recreational and sterile, homosexuality really does become just as valid as heterosexuality. "Gay rights" replaces civil rights as the defining liberal cause.

And, of course, the new value of tolerance in all things sexual also explains why not only Democrats but much of the American public have been rallying around President Clinton, whose sexual worldview mirrors their own.

Sex has become the liberals' last issue. Not that the old big-government liberalism is dead. The federal government and its bureaucracies are still intrusive. President Clinton, at his Renaissance Weekend, said that he has increased his belief in the power of government to improve people's lives. Emboldened by their recent political success and a budget surplus, liberals are likely to come up with new blueprints for social engineering. But these will be hard sells. Sex is the one issue liberals have that resonates with the whole culture.

The new political formula of being "an economic conservative but a social liberal" has wide appeal. Not only "New Democrats" but what might be called "New Republicans" are describing themselves in these terms. So are stock-market-rich yuppies and white-collar workers.

Michael Medved, in an article in USA Today, has shown that the key predictor of politics is marriage. Among voters in the November election, a majority (54 percent) of married women supported Republicans, as did married men (58 percent). Contrary to the common impression, Republicans, not Democrats, won over the "soccer moms."

But Democrats overwhelmingly won the singles vote. Unmarried men voted Democratic by a margin of 55 percent. Among single women who voted, the numbers were overwhelming: Nearly two-thirds (64 percent) of women who were single, divorced, or widowed voted Democratic.

Whatever the cause of this "marriage gap"-whether single mothers and older widows, for example, feel more dependent on the old-liberal-sponsored government programs, or whether many single men have an aversion to the conservative values of marriage-"family values" remain a defining issue. But a pro-marriage, pro-family agenda has its political downside, and many Republicans want to flee it.

Where does this leave social conservatives? They might consider tactical alliances with the often overlooked Americans who could be described as "economic liberals but social conservatives." Blacks, for example, have often become dependent on old-liberal largesse, which in turn has led to wholesale breakdown in their families. But black Americans tend to be conservative when it comes to homosexuality, abortion, and related issues. Though Hispanics have had a tradition of voting old Democratic, their strong "family values" could bring them into the Republican fold. If conservatives would refrain from immigrant-bashing, they would find that hard-working legal immigrants are nearly all cultural conservatives at heart.