Pollster Lou Harris has discovered what President Reagan is still learning, and what you and I have known all along: that in order to give people what they want, you have to be prepared to ignore what they demand. Specifically, Harris' latest poll found Americans demanding less government interference in their lives. Indeed, only 21 percent of the Harris respondents said they wanted more government regulation.

But would less government interference really make us happy? Not when 94 percent of us think the government should approve new drugs before they can be sold, when 88 percent of us want the government to be responsible for the safety of our children's toys, when two-thirds of us want the government to decide even which TV ads are misleading. What we really want is not less government interference but less government interference of the sort that makes us unhappy. And that, of course, depends on where we stand and what is being interfered with.

It has taken him a while, but Reagan is starting to catch on. He came into office prepared to listen to our demand for less government spending. He started slashing programs right and (mostly) left, and every time he swung his ax, he heard another yelp of outrage. He discovered we didn't want what we demanded. What we really had in mind could be translated: "Reduce the budget, but keep the (blank) program"-- the sum of the blanks being roughly equal to every program in the federal computer.

Members of Congress, who tend to hold office far longer than presidents, know this already. They know that they can ignore our demands, for instance, that they close the tax loopholes that are bleeding the Treasury dry. The loopholes didn't just happen; they are there because some people, including you and me, desperately want them there. If you doubt that, just imagine your own reaction if some literal-minded congressman proposed an end to deductions for mortgage interest. What we really want is an end to loopholes that benefit other people. And since all of us are someone else's "other people," few loopholes get closed.

The principle applies to government agencies of all sorts and at all levels. We demand free enterprise in general, but we want protected markets for ourselves. We demand an end to the judicial discretion that keeps turning lawbreakers back onto the streets, but we want judges to be lenient with us. We demand freedom of the press, but we want the obnoxious opinions kept out of the papers and off the air waves. We demand that the government leave us the hell alone, but we want the government not to let anybody hurt us.

We are like the fabled right-wing farmer who, having studied agriculture on the GI Bill, bought his farm with a VA loan and wired it under the Rural Electrification Program; who, having sent his children to a federally supported college on guaranteed student loans, demands an end to government "handouts" because they sap the free-enterprise spirit.

We are positively lyrical in our demand for fairness. We insist that in America, everybody should be treated equally. But while we demand fairness and equality, what we really want is a place at the head of the line. The wonder is that it took Lou Harris so long to learn the truth about us. The difference between what we demand and what we really want should have been instantly obvious to anyone who loves his automobile and hates traffic.