Answer: Kennedy declared his support for Berlin but took no action against the USSR
Explanation:
Upon his return home from the Vienna summit with Khrushchev, Kennedy demonstrated his resolve to protect West Berlin by calling up Army Reserve and National Guard units. The Soviets responded on August 13, 1961, by erecting the twenty-seven-mile-long Berlin Wall, which isolated U.S.-supported West Berlin and prevented all movement between the two parts of the city. Behind the concrete wall, topped with barbed wire, the Communists built minefields and watchtowers manned by soldiers with orders to shoot anyone trying to escape to the West. Never before had a wall been built around a city to keep people from leaving. The Berlin Wall demonstrated the Soviets’ willingness to challenge American resolve in Europe, and it became another intractable barrier to improved relations between East and West.