The presidency of Dwight D. Eisenhower began at noon EST on January 20, 1953, with his inauguration as the 34th President of the United States, and ended on January 20, 1961. Eisenhower knew how ill-prepared Vice President Truman had been on major issues such as the atomic bomb when he suddenly became president in 1945, and therefore made sure to keep Nixon fully involved in the administration. He planned for the full mobilization of the country to counter Soviet power, and emphasized making a 'public effort to explain to the American people why such a militaristic mobilization of their society was needed.' The Eisenhower administration expanded military aid to Latin America, and used Pan-Americanism as a tool to prevent the spread of Soviet influence. In the late 1950s, several Latin American governments fell, partly due to a recession in the United States.