Foy D. Kohler, 82, a veteran State Department official and authority on the Soviet Union who was the U.S. ambassador in Moscow during the Cuban missile crisis of 1962, died of heart ailments Dec. 23 at Jupiter Hospital in Jupiter, Fla.

Mr. Kohler, who lived in Juno, Fla., was a member of the Foreign Service from 1931 until his retirement in 1967, and he attained its highest rank, career ambassador. Most of his career involved the Soviet Union and the countries it borders, and the last two decades of his career coincided with some of the most difficult times of the Cold War: the extension of the Soviet sphere in Eastern Europe after World War II, the Berlin blockade and the Berlin airlift, the Korean War in the early 1950s, the uprisings in Poland and Hungary in 1956 and the blossoming of rivalries and tensions in other spheres.

For Mr. Kohler, the lesson of these events was that the rulers in the Kremlin were bent on inexorable communist expansion and that the interests of the United States required that they be met with sustained and unswerving opposition. He thus was entirely prepared for the assignment that was to be the capstone of his professional life, the ambassadorship in Moscow.

When President Kennedy appointed Mr. Kohler in 1962, Washington and Moscow were entering the fourth year of a crisis about Berlin in which Soviet Premier Nikita S. Khrushchev made successive threats to cut off Western access to the city. The most dramatic moment was the building of the Berlin Wall in 1961.

In October 1962, just two months after he arrived in Moscow, Mr. Kohler had to deal with the Cuban missile crisis. This was brought about when the Soviets placed missiles in Cuba. The United States set up a naval blockade of the island, and it appeared that the two superpowers were on the brink of war. In the end, Khrushchev agreed to withdraw the weapons from Cuba, and the United States later removed missiles it had in Turkey. One of the results of the crisis was a distinct winding down of tension over Berlin.

As the chief U.S. diplomat in Moscow, Mr. Kohler was intimately involved in these events. As a professional diplomat, he was more concerned with principles than personalities, and he admitted a certain admiration for Khrushchev.

"You couldn't help but like him just as an individual," he once said. "He was a shrewd peasant and he loved to trade repartee. He had a quick wit. It's true that Khrushchev -- especially with his de-Stalinization speech -- shook up the society and greatly eased the terror that had prevailed under Stalin. On the other hand, Khrushchev was a true believer in Bolshevism."

When his tour in Moscow ended in 1966, Mr. Kohler returned to Washington as deputy undersecretary of state for political affairs. He held that post until he retired.

For the next 11 years, he taught at the Center for Advanced International Studies at the University of Miami, and he continued to write and speak on foreign affairs. During the 1970s, he was a member of a panel of nongovernment experts who warned against Soviet intentions in the world. The group was convened under official auspices to counter the view of the Soviet Union put forth by the Central Intelligence Agency, and it led to a notable debate within the government.

Foy David Kohler was born Feb. 15, 1908, in Oakwood, Ohio. He attended Toledo University and graduated from Ohio State University in 1931. He went straight into the Foreign Service.

His first foreign assignment was as a consul in Windsor, Ontario. In 1933, he was posted to Romania, and he subsequently served in Yugoslavia, Greece and Egypt. He was in the State Department during much of World War II and worked on Near Eastern affairs. At the end of the war, he attended the founding of the United Nations in San Francisco. He also laid the groundwork for Greek war relief and an Allied mission to observe the postwar elections in that country.

He spoke Russian, and from 1947 to 1949 he was counselor of the U.S. Embassy in Moscow. He then headed the Voice of America. From 1953 to 1956, he was counselor of the U.S. Embassy in Ankara, Turkey. He also served on the State Department's Policy Planning staff and with the International Cooperation Administration, a predecessor of the Agency for International Development. He was deputy assistant secretary of state for European affairs before going to Moscow as ambassador.

In 1951, his career was nearly derailed when he and his wife were in a traffic accident in Washington. He was found to be carrying classified documents that he had removed from the State Department against regulations. He was suspended for 30 days, then sent to Turkey.

Asked about this at his confirmation hearings for the job in Moscow, Mr. Kohler said, "I believe the record of the last 10 years shows that I don't make such mistakes a second time."

Survivors include his wife, the former Phyllis Penn, of Juno, whom he met while both were serving in Romania in the Foreign Service.