Reagan Flies Back to Capital : Hails Western-Led Crusade, Says Pact ‘Within Our Grasp’

President Reagan flew back to Washington today, saluting “momentous events” taking place in U.S.-Soviet relations and proclaiming that a new Western-led “crusade for freedom . . . is well under way.”

Reagan, reporting on the results of the five-day summit in Moscow, said he and Soviet leader Mikhail S. Gorbachev had made “tangible progress” toward an agreement to scale down the superpowers’ arsenals of long-range nuclear missiles and bombers.

And he declared: “Such a treaty, with all its implications, is, I believe, now within our grasp.”

Most Upbeat Assessment

Reagan’s assertion, made just hours before he flew back to Andrews Air Force Base, was the most upbeat of any made by U.S. officials who took part in the Kremlin meetings this week.

But senior advisers who have been close to the difficult negotiations have said that so many details of an agreement remain to be resolved that they do not expect the United States and the Soviet Union to achieve such a pact before Reagan’s term ends Jan. 20.

One White House official said: “Everything’s in our grasp rhetorically. But there’s no chance realistically.”

In a sentimental speech delivered in throaty, dramatic tones, Reagan summoned memories of stirring British victories--in the Falklands in 1982, at El Alamein in World War II, on the Marne in World War I--to underline Western resolve, while at the same time forecasting an era of new amity along the East-West divide.

Speaking in the 15th-Century Guildhall, the center of civic government in London, and surrounded by the pageantry that Britain routinely summons for such events, the President predicted a relaxation in the tension that has marked East-West relations for four decades. At the same time, he also held out the possibility that the renewal he saw under way in the Soviet Union may yet come to naught.

“Quite possibly,” he said, “we are beginning to take down the barriers of the postwar era. Quite possibly, we are entering a new era in history, a time of lasting change in the Soviet Union. We will have to see.”

‘Momentous Events’

Referring to the treaty that went into effect Wednesday to eliminate U.S. and Soviet medium-range missiles and the just-begun withdrawal of Soviet troops from Afghanistan, Reagan said: “The changes we see in the Soviet Union--these are momentous events. Not conclusive. But momentous.”