AMERICAN voters - at least those not watching weekend football - got their first good look on Sunday night at the major themes of the 1992 presidential campaign.In the kickoff of the presidential TV debate season, Gov. Bill Clinton of Arkansas, widely seen as the most polished of the six major Democratic candidates, emphasized his twin themes of revitalizing the American middle class while bringing about change in Washington. Sen. Tom Harkin of Iowa, the favorite of labor unions, hammered away at the need for more jobs. Former Sen. Paul Tsongas of Massachusetts, a middle-road Democrat, spoke of rebuilding the "engine" of the economy, American business. Former Gov. Jerry Brown of California, the iconoclast of the group, pounded over and over at the need to remove the influence of private money from American politics. Gov. L. Douglas Wilder of Virginia, the least defined on issues, emphasized racial fairness and cutting government waste. Sen. Bob Kerrey of Nebraska, while pointing out his wartime experience, spoke of streamlining government and the need for a national health-care plan. For many Americans, this was their first snapshot of the Democratic field just nine weeks before the first-in-the-nation New Hampshire primary. Most of the candidates, with the exception of Mr. Brown, are little known to voters. And even though this was the first national exposure for most of them, they recognized that Americans are focused right now on the Christmas holidays, not politics. As an aide to Senator Kerrey pointed out, the main goal of all the candidates was simply to introduce themselves. Only Mr. Brown may have hurt himself. Violating the groundrules for the debate, Brown twice repeated his toll-free phone number, and appealed for funds. When moderator Tom Brokaw of NBC News tried to silence him, Brown accused the newscaster of attempted censorship. But experts derided Brown's performance. Political scientist Larry Sabato of the University of Virginia awarded Brown "the booby prize." Dr. Sabato says: "I was embarrassed for him, and for the Democratic Party." Thomas Mann, a senior political analyst at the Brookings Institution, says the Democratic candidates "were looking downright presidential until Brown got going. He really is a destructive person that manages to diminish not only himself but the others around him." The 90-minute debate, which will be followed by similar events on the other major networks, was marked by several notable moments. Kerrey told Americans that "you saved my life" with government-provided health care after he was wounded in Vietnam. Senator Harkin held up a $1 bill to ridicule calls for a cut in middle-class taxes. He noted that the cuts would save a typical family only $1 a day, adding that families need jobs, not tax cuts. At another point, Brown was spotted reading a newspaper as other candidates spoke. Analysts kept a particularly watchful eye on Governor Clinton, who had won a straw poll just hours before among Florida Democratic activists. The poll, taken every December prior to presidential election years, often indicates early strength. But with the exception of Brown, the other Democrats avoided going after Clinton directly. Rather, they rapped Mr. Bush's economic performance, while spelling out their own ideas. Analysts thought the one-minute closing statements of all the candidates were particularly effective. Excerpts: Wilder: "Thirty-nine years ago this month, I was huddled with my buddies in Korea wondering why I was asked to fight ... for freedoms for people that I didn't enjoy in America.... I came back to a segregated society, furthered my education, and secured many of the things I dreamed about.... I want all young people out there to know they can be whatever they can be. Hold to your dreams." Tsongas: "Outside of Washington where I live and where you live, the economic pain is very real.... It seems to me pretty clear that George Bush will not solve the problem because he will not even admit it.... America needs jobs. What we have to talk about is where the engine is to drive those jobs. It's manufacturing." Harkin: "Two hundreds years ago ... we said no to King George and his government of the privileged few. Isn't it ironic 200 years later we have a new King George, isolated, [who] doesn't understand ordinary, hard-working Americans?" Clinton: "I believe our country is in trouble.... The middle class is going down, poverty is exploding.... Of all the people running, I've spent the most time working on these problems: how to get and keep good jobs, how to educate our children, how to solve social problems like health care and energy." Kerrey: "We need to begin today, as Americans, to build the strongest, the best economy in the world. We need to begin by declaring that balanced trade will be the object of our nation's policy." Brown: "My campaign is about giving you power.... It is about taking back democracy from those who have distorted it and who are running it into the ground."