Why is George Bush ahead in the polls? The answer of choice for most of the media runs like this explanation from Newsweek: "George benefits from the Republicans' well-honed marketing skills, taste for hardball tactics and willingness to exploit `hot button' issues." It is also an answer that reveals an extraordinary contempt for the political intelligence of the public.

This contempt is not new. Consider the relentless efforts to explain President Reagan's popularity by his pleasing personality, his slick rhetoric, the skill with which his public-relations team has " sold" him.There is a profound reluctance to ascribe his popularity to anything he has actually done. Apparently it is possible to fool all the people - if not all the time, then at least eight years at a time. Or so our media seem to think.

However, the simple truth is that the campaign of 1988 is, as most presidential campaigns are, a contest between ideologies. If Bush wins, it is because more Americans, at this moment in their history, prefer to think and feel in a conservative way rather than a liberal way.

The campaign has been perfectly traditional. Polemical criticism has been no more strident or "unfair" than in the past. Moreover, the campaign has focused quite adequately on the real issues, though in very general terms.

Foreign policy: It is obvious to every American, as well as to foreign observers, that George Bush will favor larger military expenditures than will Michael S. Dukakis. It is also obvious that his foreign policy will be closer to President Reagan's than will Mr. Dukakis's.

Even the flap over the Pledge of Allegiance - dismissed by so many commentators as pointless and demeaning - has a bearing on perceived differences in foreign policy. Bush has aligned himself with the nationalist temper so visible among Americans, while Dukakis's attitude suggests a more familiar liberal-internationalist perspective.

How these contrasting approaches would work themselves out in actual foreign policy is unclear. But there is little doubt that a majority of Americans feel more comfortable with, and have more confidence in, the Reagan-Bush posture than the Carter-Dukakis one.

Economic policy: There has been considerable disbelief about George Bush's call for a "semifreeze" in government spending while economic growth permits a gradual reduction of the deficit. "What programs will you cut?" the media keep asking. But a semifreeze does not involve radical cuts. Rather, it calls for a slowing-down in the rate of growth in spending.

It is highly probable that Dukakis would follow this strategy, too. Though his advisers are privately persuaded a tax increase is necessary, Congress is unlikely to give him an increase large enough to have a material effect on the deficit. Nor is Dukakis recommending any such tax increase. It is, then, perfectly sensible for Americans to pay little attention to supposed differences in economic policy.

Social policy: The overwhelming majority of Americans are in favor of the death penalty, are more worried about crime than about the homeless and think the courts have gone "too far" in protecting the rights of criminals over the safety of their victims. Bush more faithfully reflects the anxieties of the populace.

A victory for Mr. Bush will mean nothing less than a victory for his ideas.