Politics, like medicine, is a peculiar science. There are myriad experts, specializations, data, jargon and technologies. But the explanation of a medical event often involves some hoary maxim, such as, "Eat and exercise sensibly." And political events often are explained by old parables, such as:

A meticulous entrepreneur decided to manufacture dog food. He lavished attention, and Harvard Business School graduates, on the ingredients, can, label, market research, advertising, display. Yet the stuff did not sell. So he snuck away from his battalions of experts and asked a storekeeper, "What's wrong?" The storekeeper said: "The dogs don't like it."

Today's question is: Is Jack Kemp's presidential campaign lagging and does the parable explain why?

For several years he has done everything conventional wisdom suggests. He has whipped around the country like a sirocco, speaking for candidates at party functions -- wherever creamed chicken and a stalk of broccoli have come together. He has become identified with the bread-and- butter issue of American politics -- the cost and the jobs required to acquire bread and butter. Although he toils in the proletariat of American politics, the House of Representatives, his name preceded that of a lordship of the Senate on the Kemp-Roth tax-cut legislation. He is tied with hoops of steel to Reaganomics, and Ronald Reagan's economy is soaring.

And yet, here are the results of two Harris polls asking a national cross- section of 1,305 voters to select a "first choice" -- from a list of presidential candidates: Bush Baker Dole Haig Kemp Kirkpatrick If, a year ago, political observers had been told that Bush would lose more than 20 percent of his strength, yet Kemp also would lose strength, the observers would have been mystified. Kemp says he is neither puzzled nor dismayed. Yes, politics often is an exercise in "spin control," the art of putting the best interpretation on events. But Kemp's spin on the Harris poll is convincing.

He says that polls, especially those among the general electorate rather than activists, are not particularly important for him now. They are primarily reflections of name recognition, and a vice president has an advantage.

Kemp thinks his disadvantage can be fixed quickly. Even before there was television, things sometimes moved fast in presidential politics. In 1940, Wendell Willkie was the choice of just 3 percent of Republicans in early May and yet was nominated in late June. With television, Gary Hart in 1984 went from approximately 6 percent recognition to 76 percent in one week after the New Hampshire primary.

So, Kemp's plan is the usual plan: to win something early. To that end, he says, his task is to energize the grass roots, and especially the people who worked for Reagan in 1980 and 1984. Today, tucking into a lunch of swordfish, prior to flying to Philadelphia to campaign for a candidate, he has just returned from New Hampshire. In the next two months he will make four trips to Michigan, where a rococo procions begins (I am not making this up) this May. (In 1980, in a very different procar Michigan governor, trounced Reagan 57 percent to 32 percent.)

Such politics does age a boy. At 50, Kemp is 11 years younger than Bush, but he is a grayhaired grandfather. An opinionated grandfather. I once asked him to defend the indefensible: "Why don't you like baseball?" His crisp reply: "No quarterback." That give- me-the-ball-dammit spirit irritates many congressmen who emphasize collegial values. But his spirit, at least, is presidential.

"Politics," he says, "is action." Today the new ideas, from enterprise zones to aid for insurgencies destabilizing the Soviet empire, come from the center- right. Liberalism's negative tone of voice, he says, is what conservatism's was 20 years ago: "You can't do that!"

Kemp can do something Vice President Bush could not gracefully do even if Bush were inclined to do it, which he certainly is not. Kemp can, and does, strongly indicate that Jeane J. Kirpatrick would be his secretary of state, a semi-promise that is red meat for Republican activists.

That is just one reason why it is premature for the people who are paying attention to these early stages of the nomination contest to say that Kemp, like the dog food, is not a marketable product. Another reason is: people now paying attention are, strictly speaking, peculiar, meaning they are unlike the inattentive majority of Americans.