President Reagan's economic policies are unfair. Interest rates are out of control. Unemployment is far too high.

President Reagan is a strong leader. He is effective in dealing with Congress. He represented the United States well on his recent European trip. He is liked by three of every four Americans.

That is a summary of what White House pollster Richard Wirthlin's surveys are reporting at the 18-month point of the Reagan presidency. The Wirthlin polls also suggest that Reagan has defused the nuclear freeze issue by his arms control initiatives and has generally improved his standing on foreign policy, even as it is slumping on economic performance.

But the public perception of the Reagan foreign policy, like the policy itself, is clouded by events in the Middle East. Two of three Americans think the U.S. response to the Israelis after the invasion of Lebanon was too weak even though the Palestine Liberation Organization has the lowest standing of any institution or individual measured in the surveys. Americans overwhelmingly dislike Israeli Prime Minister Menachem Begin.

Overall, the dualism of Reagan's standing with the electorate can be expressed in a single sentence: Three of 10 Americans who disagree with Reagan policies remain supportive of the president. In Wirthlin's polls, as in some published surveys, Reagan's standing has now inched upward to slightly above 50 percent after plummeting early in the year.

"The reason it's stabilized is that people like Ronald Reagan," says Wirthlin, taking comfort where he can find it. Whether this good feeling will withstand an aborted economic recovery is anybody's guess.

If you're wagering, don't bet that deputy chief of staff Michael K. Deaver's well-advertised plan to leave the White House at the end of the year will happen. Nancy Reagan, inevitably well-informed on personnel changes that affect her husband's well-being, is telling people that Deaver will stay. Others at the White House are giving similar hints despite Deaver's disclaimer that his plans haven't changed and that he hasn't yet sat down with the Reagans to discuss his future.

But in an administration where the inevitable private tensions of shared leadership are becoming public ones, Deaver increasingly is perceived as the glue who holds the collective together. This perception, and Deaver's loyalty to the Reagans, could lead him to remain at the White House despite personal and economic considerations which argue strongly in favor of a return to the private sector while Reagan is still president.

Deaver, incidentally, is responsible for the White House employment of maverick pollster Arthur Finkelstein, who is working against Wirthlin in the New York gubernatorial elections. (Wirthlin's candidate in the bitterly contested GOP primary is the favored Lew Lehrman, while Finkelstein advises rival Paul Curran.) For the White House, Finkelstein is more of an idea man than a pollster, specializing in media events such as the president's "spontaneous" drop-ins on disadvantaged individuals and institutions.

Collectors of essential Reaganisms will treasure the comment that filtered out of the National Security Council meeting on June 29 where the president went with his inclinations, and those of counselor Edwin Meese III, and decided that the United States would not sign the international Law of the Sea Treaty.

"We're policed and patrolled on land and there is so much regulation that I kind of thought that when you go out on the high seas you can do what you want," opined the leader of the Free World.

Damn the torpedoes, full speed ahead.

Longtime Reaganite Edwin Gray, onetime Reagan press secretary in California and now director of the White House Office of Policy Information, is returning to the San Diego savings and loan organization (now renamed Great American Federal Savings) from whence he came . . . White House advisers are pleased enough with Reagan's improved performance in prime time press conferences that they are saying all news conferences will be at night from now on. They're not so pleased, however, that anyone is promising that the frequency of news conferences will be increased.

In 1979, Prof. George P. Shultz of the Stanford University Graduate School of Business said that foreign countries regard the United States as "the Prince Hamlet of world affairs, powerful but indecisive, lacking in resolution and reliability, with results that are dangerous for everyone."

Now that the euphoria over Al Haig's departure is wearing off, some White House advisers are worrying that Shultz may be a Hamlet in disguise, moving too cautiously in the wake of his confrontational predecessor.

"Shultz is very good but he's also very cautious," said one adviser last week. "This means that the learning curve may be slow during a period when we may not have much time."