PRESIDENT REAGAN campaigns across America as if voters were the sort of people androgynous pop rocker Boy George describes in "Karma Chameleon." "I'm a man without conviction," George sings. "Loving would be easy if your colors were like my dreams -- red, gold and green."

No one seeks to identify himself with boldly colored dreams more than Ronald Reagan. But, the president is simultaneously a candidate who asks little in the way of strong convictions from his audiences, who appeals to their emotions rather than leads them to think about the issues of the day.

In a speech the other day to 20,000 supporters at a high school football field in Endicott, N.Y., Reagan spoke a classic line that captures the essence of his 1984 campaign. "The main difference between us and the other side," he said, "is we see an America where every day is the Fourth of July, and they see an America where every day is April 15."

On the level of imagery and emotions, that line is brilliant. On the level of substance, it is at best vacuous and at worst insidious. And yet, that single sentence sums up the Republican strategy.

The strategy, rooted in sophisticated surveys of public attitudes, rests on an analysis of voters that goes something like this: issues, and the opinions people hold about them, sit on the surface, sometimes calmly, periodically flaring up, then out again. Beneath the surface, meanwhile, are certain broad values, which people hold onto strongly and which hardly ever vary.

Instead of concentration on issues, the president focuses on those deeply held values. They are the values celebrated on occasions like the Fourth of July -- flag, family and freedom. Further, Reagan blatantly associates his presidency and his candidacy with the mood that led Time magazine to emblazon its cover with "I C U.S." As a visual, the Reagan campaign could hardly have asked for more.

The flip side of the strategy obviously is to attempt to link Walter Mondale and the Democratic Party with what Republicans call "doom and gloom" -- or the dour attitude many Americans have when they file their income tax forms. In this way, the Reagan campaign dismisses discussion of the nation's problems as so much pessimism.

Whether this is presidential leadership is something else. The country could neither provide essential services to its citizens nor protect the freedoms they celebrate on the Fourth without the revenues income taxes bring in. But instead of explaining that taxation is the means by which a society pools resources for the good of the whole, Reagan's rhetoric feeds the cynicism that leads to tax evasion and general disaffection with government.

It could be argued, of course, that everyone knows basically where Ronald stands, so what need is there for him to discuss the details of the policies? The fact is, however, the way Reagan is campaigning gives voters little ideas as to how he would govern between 1985 and 1989, if he is re-elected.

The president says he is against tax increases; and yet, he not only signed the supply-side tax cut of 1981 but also the tax-increase package of 1982. Would he veto any tax increase in the next four years? He doesn't say.

He says he's for tax simplification, but would he choose a flat tax, a value-added tax or a direct sales tax? He doesn't say.

The president says he's for a balanced-budget constitutional amendment, but, when he has been free to do so in his annual recommendations to Congress, he has yet to submit a balanced budget. Would he propose a balanced budget in the next four years? He doesn't say.

The style of Reagan's campaign borrows from the concept of rock- music videos and Pepsi Cola commercials. These razzle-dazzle productions are short on story and substantive message and long on quick bursts of sight and sound stimulation. They don't call on their viewers to think deeply, just to rock along with the images.

If there is one difference, it is that many music videos appear dark and dreary, sometimes even morbid, almost always culturally unconventional, while Reagan is unremittingly upbeat and endorses conventional values.

The president hardly ever makes himself available for the kind of sustained questioning that Mondale and vice presidential candidate Geraldine Ferraro take as a natural part of campaigning -- the better for Reagan to keep at bay nagging talk about such issues as the deficit, poverty, arms control and the nation's economic future.

The Reagan campaign aims for maximum impact in the 90-second spot on the nightly TV news. That is, it is designed to appeal to voters more and more conditioned to receive visual messages. The marketing of President Reagan follows much the same principles that guide the Pepsi commercials starring Michael Jackson.

Perhaps this helps to explain why the latest Washington Post-ABC News Poll found Reagan leading Mondale by 60 percent to 38 percent in the 18-to-30 age group. Relatively new voters, who grew up in the post-Yellow Submarine era, favor the 73-year-old Reagan by a wider margin than older voters. It is his demeanor, communicated on television, that leads young voters to consider him a "leader."

It also may help explain why national polls have found Reagan to be more popular personally than his policies. Millions of voters who disagree with Reagan and hold views close to Mondale's on such major issues as abortion and arms control say they plan to vote to re-elect the president. The themes and visuals of the Reagan campaign appeal to Americans' economic self-gratification -- if you see yourself as better off, vote your pocketbook.

"I'm a man without conviction" -- that haunting line from Boy George -- pictures the voters as the Reagan campaign treats them.