Sen. Charles Percy (R.Ill.) left Moscow today confident that he had hammered home to the Kremlin leadership of Leonid Brezhnev that a new American administration means a new, constructive approach to strategic arms control, the toughest and most threatening problem in the superpower relationship.

His visit has sparked remarkable press attention here and at home, as though the two countries feel ready for new steps that eventually could lead to historic achievements. Yet, there is an unmistakable sense of deja vu about the last three days of talks between the newly powerful Percy, who is expected to become chairman of the Senate Foreign Relations Committee, and the Kremlin leaders.

Turn the calendar back four years to the first days of the Carter administration, or 12 years to the first days of the Nixon presidency, or even go back 16 years to the Johnson administration's first heady days under a landslide mandate; history shows that like virtually everything else about Soviet-American relations, hopes for successful arms control agreements are almost always dashed within the span of a president's four-year term.

In each case, new administrations sought strategic arms limitation treaties that would usher in a new era of cooperation and trust between the world adversaries. Circumstances varied from year to year, but comprehensive achievements have lagged far behind aspirations.

At present, three major agreements -- SALT II, an underground test ban treaty and a treaty governing peaceful uses of atomic explosions -- have been languishing for as much as six years without ratification by either country.

In addition, after years of arcane and sometimes subtle negotiations, no significant breakthroughs have occurred on treaties covering mutual balanced force reductions and theater nuclear forces in Europe, a comprehensive nuclear test ban, conventional arms transfers, or antisatellite weapons systmes. Meanwhile, research speeds forward on new types of strategic weapons.

Percy's assertion that he is "relatively optimistic" about early progress to re-open negotiations on the centerpiece SALT II treaty and related matters must be weighed against this unpromising record.

If Brezhnev, Defense Minister Dmitri Ustinov and Foreign Minister Andrei Gromyko now understand that this key treaty is dead in its present form, as Percy thinks they do, there is still little reason to believe this knowledge will yield a sudden breakthrough.

The Brezhnev Politburo, which came to power in 1964 and has already dealt with President-elect Ronald Reagan's four immediate predecessors, may prefer Republicans to Democrats in Washington -- as many Soviet officials now can be heard saying. But by the very nature of the way it works, painstakingly constructing internal consensus for every important position, the Politburo is not susceptible to swift abandonment of one position for another.

Percy said Gromyko shocked him by opening the third day of talks by harping again, as Brezhnev and Ustinov had earlier, on U.S. failure to ratify SALT II. That solid phalanx of reproval from the Kremlin's inner circle makes clear that Moscow will make every attempt to ensure that Washington pays dearly for the privilege of going back to the negotiating table.

At the same time, there are serious external and internal pressures on the Soviet leadership that could spur Kremlin interest in trying to improve relations.

The invasion of Afghanistan last December fulfilled some of Moscow's historically expansionist impulses and saved an ideological puppet, but created a foreign relations nightmare for the Soviets far more damaging than the 1968 invasion of Czechoslovakia. World nervousness, especially in key West European trading partners, about a possible Soviet intervention in Poland increases the pressure for some gesture.

Any low-cost act of friendliness to Reagan and the Republicans, such as the wide access and positive media treatment given here to Percy, that could defuse these war-related fears abroad might seem worthwhile to the Politburo as it analyzes its situation during the approach of the 26th party congress next February.