Answer:
Kennedy worried that actions on the part of the United States might start a war with the Soviets.
Step-by-step explanation:
The Cold War was a difficult period in human history, which every action could lead to a physical conflict. All the diplomacy would be taken carefully. The Berlin Wall was an East German initiative that was under Soviet control. Because of that, Kennedy was afraid that his actions were seen as a threat to the Soviet government, leading to a real conflict.