Answer:
The Monroe Doctrine, in asserting unilateral U.S. protection over the entire Western Hemisphere, was a foreign policy that could not have been sustained militarily in 1823. Monroe and Adams were well aware of the need for the British fleet to deter potential aggressors in Latin America.
U.S. diplomat Allan Lightner attempted to cross Checkpoint Charlie to attend the opera in East Berlin. East German border guards demanded to see Lightner’s passport, but he refused on the grounds that only Soviet officials had the authority to inspect his papers. He only got through the checkpoint after he left and returned with a complement of armed U.S. soldiers and military jeeps. When East German officials continued to deny Americans entry into East Berlin, U.S. General Lucius Clay put on a show of force by moving 10 M-48 tanks into position around Checkpoint Charlie. The East Germans’ Soviet allies responded by positioning three-dozen T-55 tanks near the eastern border. On October 27, 10 of them rode forward to meet the American armor. For some 16 hours, the two sides stared each other down in one of the only armed confrontations of the Cold War. The potential for World War III was only averted when President John F. Kennedy contacted Soviet leader Nikita Khrushchev and convinced him to withdraw his tanks. A few minutes later, the American M-48s also left the scene.
