The new U.S. arms proposal to be presented in Geneva today is the latest in a flurry of moves by Moscow and Washington that has suddenly invigorated arms control negotiations that languished for years. Unexpectedly, the two superpowers are talking actively about serious issues in ways that suggest at least the possibility of genuine movement in the weeks and months ahead.

The flurry of sudden maneuvers back and forth is partly an international public relations exercise designed to enhance the positions of Ronald Reagan and Mikhail Gorbachev on the eve of their Nov. 19-20 summit meeting, but the import and potential impact go far beyond mere posturing. The game is being played with the coin of vitally important matters: offers of massive cuts in offensive nuclear arms, a Siberian radar whose construction has outraged the U.S. government, the present and future of the only U.S.-Soviet treaty curbing defensive weaponry, the health of a renowned Soviet dissident.

As Secretary of State George P. Shultz prepares to fly to Moscow to discuss a long list of summit items with Soviet leader Gorbachev early next week, the chances seem good for additional maneuvers in the superpower competition.

It is too early to say, based on the sketchy reports available, to what extent the new U.S. arms proposal departs from earlier offers made by Washington at the bargaining table in Geneva, and particularly whether it meets Soviet demands for strict controls on space-based weaponry. President Reagan said the new plan "builds upon" earlier U.S. offers as well as the "positive elements" in the latest Soviet arms proposal.

It is clear, however, that by deciding to present a detailed and comprehensive offer at this moment, Reagan is keeping the arms control ball in play with the Soviets. This was the strong recommendation of the major Allied leaders who met with the president in New York last Thursday. The issues of when and how to present a new U.S. proposal -- more than the substance of the offer -- are reported to have been contentious within the inner councils of the administration.

The launching platform for all this was what seemed to be almost an offhand decision by Reagan last March 11 to make a tangible bid for a summit meeting with Gorbachev. Soviet leader Konstantin Chernenko had died a few hours earlier.

With only a few minutes' discussion with his advisers, Reagan decided not to go to Moscow for Chernenko's funeral but to invite Gorbachev, who was then being installed in office, to pay an official visit to Washington. No conditions were attached to the offer. After some jockeying about place and time, in early July the two leaders announced their November date in Geneva.

"The Soviets see this summit as their one clear shot at influencing American policy and seeing whether the Reagan administration is really interested in doing business with them," said Raymond L. Garthoff of the Brookings Institution. He is a former State Department official who recently published an extensive and authoritative history of U.S.-Soviet relations over the past 15 years.

And, in view of the ragged state of relations between Moscow and Washington since the December 1979 Soviet invasion of Afghanistan and the slim possibilities of decisive improvement, "arms control has pushed itself back to the center of attention whether anybody really wanted it to or not," according to Garthoff.

Gorbachev announced in his Time magazine interview around Labor Day that arms control is his No. 1 priority for the summit. In late September Gorbachev made the point more tangibly -- and began the period of intense presummit maneuvering -- by sending Foreign Minister Eduard Shevardnadze to the White House with news of a Soviet offer to cut nuclear arms by 50 percent in return for U.S. curbs on the proposed Strategic Defense Initiative (SDI), or "Star Wars" space defense, and dispatching Soviet negotiators to present the plan in the arms talks in Geneva.

Moscow's offer was far from acceptable to Washington and in some respects withdrew earlier Soviet concessions. Nonetheless, it was by far the most specific and most dramatic Soviet arms proposal of recent years and contained, Reagan said yesterday, "certain positive seeds we wish to nurture."

The U.S. administration sought for several weeks to shift the focus of international attention from arms control to regional conflicts such as Afghanistan where the Soviets are widely seen as aggressors. Reagan's address last week to the United Nations, proposing new ways to deal with five regional disputes, was the centerpiece of this U.S. effort.

Yesterday's announcement of a new U.S. offer in the Geneva negotiations brings arms control back to center stage despite the administration's best efforts to the contrary. Announcing and presenting the offer now makes possible a Soviet rejoinder before the summit meeting with Reagan.

In the confidential negotiations in Geneva, according to U.S. sources, Soviet officials have suddenly begun talking with unusual urgency especially concerning intermediate-range weapons. New Soviet proposals in this area, while far from being acceptable to Washington, contain some elements that are welcome here and others that could appeal to Western European allies.

While all this was going on in the main tent, Moscow was making its first proposal to do something about its phased-array radar at Krasnoyarsk in Siberia, which Washington has charged is in violation of the 1972 Antiballistic Missile (ABM) Treaty. The Soviet proposal is unacceptable here but is recognized as a breakthrough toward a possible settlement later.

The Soviet bid to remove the shadow of Krasnoyarsk from the ABM treaty came as the Reagan administration reinterpreted what the treaty provides in the way of limits on SDI testing and development, and then announced it would stick with the original interpretation for now.

This, like the Soviet decision to permit Yelena Bonner, wife of Soviet dissident Andrei Sakharov, to travel to the West for medical treatment, was a part of multifaceted presummit maneuvering.