CAIRO -- Hosni Mubarak's Egypt is a cautious, consensus-seeking regional power, content to plod with the tortoises after the country had raced with the hares under Gamal Abdel Nasser and Anwar Sadat. If ever a nation deserved a breathing spell, it was Egypt at the time Mubarak came to power six years ago.

Events are now conspiring to bring Egypt back to the center of Arab politics and to end that period of relative isolation and introspection.

The Palestinian revolt against Israel and growing Arab concern about the course of the Iran-Iraq war have broken the psychological deadlock that gripped the Middle East in recent years and have given Egypt important leverage over regional issues.

This in turn raises questions about Egypt's peace with Israel and Egyptian willingness to help defend Arab interests in the Persian Gulf.

Mubarak, who embarks this weekend on a trip to Washington via Europe, remains determined to avoid the kind of big risks and shocks that were favorite tactics of his visionary predecessors.

This is likely to mean disappointment for Arab hard-liners who want Egypt to be tougher on Israel and for American policy makers who are looking for ways to reduce the expense and exposure of the American fleet operating on the edges of the Iran-Iraq war. But it will keep Mubarak in tune with Egypt's own mood of caution at the moment.

American Jewish leaders who saw Mubarak in Cairo this week were told that he would not sacrifice his country's peace treaty with Israel to improve ties to the other Arab states.

Asked later in an interview about calls from Egyptian politicians for a break with Israel as a protest against Israeli repression of the Palestinian disturbances, Mubarak responded:

"If withdrawal of the Egyptian ambassador to Israel would help solve this problem, I would not hesitate at all. But it will not lead to that."

Mubarak displays the same pragmatic stance in his dealings with the Persian Gulf conflict, where Egypt's ability and willingness to intervene are limited by factors as diverse as lack of a strategic airlift capability and a strong current of public opinion against such an involvement.

Egyptians have not forgotten the disaster that struck their army in Yemen when Nasser committed troops there in the 1960s. And fundamentalist sheiks in Cairo's mosques have been hammering recently on the theme that Egyptian troops should not be fighting against Iran when they will not be used to fight Israel.

Mubarak's innate caution was demonstrated by his decision initially to omit Iraq from the list of Persian Gulf and Arabian Peninsula states that he visited last week. He made his decision after being told by the smaller sheikdoms hosting him that they wanted to avoid giving the appearance of participating in an anti-Iranian alliance.

After Iraq screamed long and loud, Mubarak gave in and added Baghdad to the tour. But he emphasized at each stop that his country had no intention now of committing combat units to the gulf.

It is an exaggeration to say that the other Arab states are turning back to Egypt because they are now more afraid of Iran than they are of Israel. But a kernel of truth lies in that formulation, which recognizes that Egypt's reemergence as a political pivot point for the region will reestablish an important linkage between the Palestinian-Israeli confrontation and the stability of America's allies in the gulf.

That such a linkage existed was a fundamental belief of the Nixon, Ford and Carter administrations, which cited the need to ensure stability for the oil-producing regimes of the gulf as justification for heavy American involvement in Middle East peace efforts.

But the angry Arab reaction to Sadat's 1979 peace treaty with Israel broke that link by removing Egypt as the bridge between Palestinians and the gulf and by removing the credibility of Arab war threats against Israel.

The Reagan administration ignored the linkage concept, and dropped the U.S.-Egyptian-Israeli alliance that Sadat sought to construct. Instead, Alexander Haig and then George Shultz put all their efforts into a strategic relationship with Israel.

But the Reagan administration failed to find ways to exercise influence at a regional level, where Israeli military might is inappropriate for today's problems and Egypt's strength faces clear limits. It is small wonder that some taxpayers have begun to question the utility of the tens of billions of dollars that Americans have lavished on building military machines for these two countries.