"Mutual support and collective defense" was the keynote of a public forum presented by the Fourth Annual Assembly of the North Atlantic Treaty Association at Kresge Auditorium yesterday.

In an afternoon session, Admiral Jerauld Wright, USN, Supreme Allied Commander Atlantic, and his staff briefing team explained the mission of NATO and its capacity for preventing aggression.

Admiral Wright estimated Russia's military strength at 2.5 million men, 18,000 planes and 2,700 ships, with another 3,300 planes as flying escorts. But perhaps the greatest threat, he said, was the Reds' fleet of 450 submarines.

NATO Unity Prime Deterrent

Estimates of NATO strength remained secret for security reasons, although the Admiral admitted that the allied forces were considerably smaller than the Soviet armies. Despite their military strength, however, the Russians have "the patience and the realism" not to launch an attack while they are convinced of swift and united retaliation, Admiral Wright declared. "Our ability to convince them of this is the primary deterrent to aggression," he emphasized.

Spaak Addresses Wellesley

NATO chief Paul-Henri Spaak called yesterday for a union of all the forces of the West to win the global struggle with Communism.

The secretary general of the 15-nation Atlantic Alliance voiced hope that United States acceptance of this idea "will not be too late."

The wisest in continental Europe understand this, said Spaak in a lecture prepared for Wellesley College.