It is not easy to be Ronald Reagan preparing for a summit with Soviet leader Mikhail Gorbachev. In addition to wanting you to keep your facts straight on missile defense, which hasn't turned out to be easy, your advisers also want you to be yourself, as in the phrase, "Let Reagan Be Reagan." But these advisers do not agree on the definition of this all-purpose slogan.

Conservatives expect Reagan to be a "freedom president" at Geneva. They mean that he should speak bluntly about human rights, or the lack of them, in the Soviet Union. They would like Reagan to tell the Soviets that better commercial relations with the United States depend on improving Soviet treatment of dissidents and easing restrictions on emigration of Soviet Jews. They want Reagan to make a point about barbarous Soviet conduct in Afghanistan.

Less ideological advisers want Reagan to be a "peace president." They say history will judge him on whether he left the world a safer place than he found it. They know that each of Reagan's six predecessors produced arms-control agreements and that he has produced none.

These expectations put the president on the spot at the summit. Reagan campaigned in 1980 on the premise that a U.S. military buildup, subsequently delivered by Congress, would lead the Soviets to bargain seriously for arms reductions. He took a highly moralistic position on human rights, naively trying to shame the Soviets in the court of public opinion. His policies have yet to show results.

The Geneva summit is another chance for Reagan, maybe his only chance, and certainly a big one. He could return with no prospects for a future arms-control deal and no Soviet concessions on human-rights issues. This prospect has to trouble a president who strives for victories and practical accomplishments.

For all of the fanfare on arms control, it is human rights that offers Reagan a chance of limited success. He has finally accepted the counsel of former president Richard M. Nixon that tough public posturing on human rights can be counterproductive in persuading the Soviets to change their ways. Meeting with Jewish leaders in September, Reagan told them that "we don't intend to stab the Russians in the eyeballs" because this is an action that produces great pain but does not encourage a change in behavior.

At the same time, Reagan has wisely avoided the temptation to become so absorbed in arms control that he puts human rights on the back burner. He knows that he must raise human-rights issues forcibly with Gorbachev or run the risk that the Soviets will conclude that they do not really matter to him.

In recent interviews, Reagan has shown that he understands the delicacy of his position. He told wire service reporters last week that he didn't want to put Gorbachev "in a corner where he can't give in because he would appear in the eyes of his own people as if he's taking orders from an outside government."

Reagan could follow this up at the summit by making the point that the American people, under any president, are going to demand improvement in human rights as a condition for better U.S.-Soviet relations.

"If you pull out the thorn, the wound heals," says Jerry Goodman, director of the National Conference on Soviet Jewry. "And the thorn is the creation of Soviet policy."

There are some signs that the Soviets may understand that a relationship exists between the improved relations they seek and human rights. Recent gestures, including the release of Yelena Bonner and Gorbachev's willingness to listen to human-rights complaints from Secretary of State George P. Shultz may indicate Soviet awareness that Reagan speaks for civilized mankind when he calls for increased Jewish emigration, release of dissidents and uniting families.

The Soviets will never acknowledge that their policies are wrong. But if Reagan can make them realize that practical benefits will flow from a different course of conduct, the summit will have been worth the hoopla. And it might then be said of the president that he will have contributed both to peace and to freedom.

Reaganism of the Week: Asked by reporters Wednesday whether he is "raring to go" at the summit, the president said: "I'm kind of looking forward to it, yes. It's time we stopped this futzing around."