This week, as Americans celebrate the 227th anniversary of the Declaration of Independence, smokers in New York will huddle outside once smoky bars, prevented by a new law from lighting up inside, and lovers in Texas will go home disencumbered of the state's anti-sodomy law, which the Supreme Court overturned on Thursday. The smokers and lovers can trace their new status to Thomas Jefferson's manifesto, in particular the four-word phrase that rounded out his list of inalienable rights. As participants in what we have come to call the culture wars, they are the losers and winners of the pursuit of happiness.

For more than two centuries, Jefferson's phrase has hovered over this fractious churning, drawing in as many combatants as there are notions of happiness. While most Americans can agree on definitions of life and liberty, the Declaration's first two inalienable rights, happiness is another matter. In a nation of immigrants and strivers, dropouts and resisters, sectarians and self-help gurus, Jefferson left behind an endlessly mutating set of fighting words. What he left vague, generations have vied to spell out, by force of law or just by force.

With all due respect to life and liberty, it is this third battleground — characterized not as a fixed goal but a constant chase — that both animates Americans' daily lives and ties them in knots.

Among its other tangles, the pursuit underlies two enduring strains of American unhappiness: the culture wars and the ravenous consumer culture.

This contradiction is essential to the national identity. Happiness "doesn't have any legal meaning," said Richard A. Posner, a federal appeals court judge who has written about rights and society. "Happiness is not a word on which you can found a lawsuit." Yet it shapes American life in both broader and more paradoxical ways: the pursuit of happiness is the defining passion of a country whose signature voice is the blues.

This holiday, you can see this pursuit everywhere: in the booty-centric videos of MTV, the balloon-filled shopathons at appliance dealers, the expanses of the cultural landscape devoted to cooking or yoga.

It is at the mall and in the dull machinations of local government, where last week a Manhattan woman, protesting restrictions on dancing in most city nightspots, offered her own spin on Jefferson: "I have a right to life, liberty and the pursuit of happiness," said Jen Miller, who belongs to a group called Dance Liberation Front. "And what is the pursuit of happiness if not dancing?"

When Jennifer Lopez sings, "Don't be fooled by the rocks that I got, I'm still Jenny on the block," she means that she still shares her fans' pursuit of happiness, even if she has personal shoppers to score many of the essential accessories.

To Jefferson and his contemporaries, the meaning of happiness was clear and relatively circumscribed, said Pauline Maier, professor of American history at the Massachusetts Institute of Technology and author of "American Scripture: Making the Declaration of Independence."

"I don't think it meant pleasure in our sense of carnal pleasures or material wealth," she said. "Happiness demanded a good government. That seems so crazy to us. But when they spoke of the ideal, they used biblical language: `to be at peace under your vine and fig tree with none to make you afraid.' "

For the founders, children of the Enlightenment, the pursuit of happiness replaced older imperatives like religious or filial duty, an upheaval to which Jefferson wisely did not call attention.

Yet happiness is not a fixed quantity, and pursuit by its nature keeps keeping on, as they say in the rap game. As definitions of happiness multiplied over time, the pursuit doubled back on itself. Though happiness seems a non-zero-sum game, meaning one person's joy should not prevent another from being happy, in practice the multiplicity of happiness has led to conflict. In a diverse society, the pursuit of happiness inevitably becomes a threat.

"At some level it's the beginning of the culture wars," said Roger Pilon, director of the center for constitutional studies at the Cato Institute, a libertarian research group. "People understand the First Amendment protection of free speech, but we have a hard time going beyond that to understanding the protections to action generally, like the pursuit of happiness."

The culture wars — which have escalated since the 1960's, when even Hubert H. Humphrey called for a "politics of happiness" — arise from competing claims to happiness, the individual and the collective, said Stanley Fish, dean of the college of liberal arts and sciences at the University of Illinois at Chicago.

"There's an abiding struggle," he said, "between those who embrace the libertarian ethic of complete freedom, pursuing whatever happiness you want as long as it doesn't harm anyone else, and others who say that what is required is a society that rewards virtue, that actively discourages unhealthy activity, in order to allow the most happiness for the most people."