Kennedy would have found a way to withdraw all American instructors and advisors [from Vietnam]. But ... I do not believe he knew in his last weeks what he was going to do." Sorensen added that, in his opinion, Vietnam "was the only foreign policy problem handed off by JFK to his successor in no better, and possibly worse, shape than it was when he inherited it." U.S. involvement in the region escalated until his successor Lyndon Johnson directly deployed regular U.S. military forces for fighting the Vietnam War. After Kennedy's assassination, President Johnson signed NSAM 273 on November 26, 1963. It reversed Kennedy's decision to withdraw 1,000 troops, and reaffirmed the policy of assistance to the South Vietnamese. American University speech On June 10, 1963, Kennedy, at the high point of his rhetorical powers, delivered the commencement address at American University in Washington, D.C. Also known as "A Strategy of Peace", not only did Kennedy outline a plan to curb nuclear arms, but he also "laid out a hopeful, yet realistic route for world peace at a time when the U.S. and Soviet Union faced the potential for an escalating nuclear arms race." Kennedy wished to discuss a topic on which too often ignorance abounds and the truth is too rarely perceived—yet it is the most important topic on earth: world peace ... I speak of peace because of the new face of war ... in an age when a singular nuclear weapon contains ten times the explosive force delivered by all the allied forces in the Second World War ... an age when the deadly poisons produced by a nuclear exchange would be carried by wind and air and soil and seed to the far corners of the globe and to generations yet unborn ... I speak of peace, therefore, as the necessary rational end of rational men ... world peace, like community peace, does not require that each man love his neighbor—it requires only that they live together in mutual tolerance ... our problems are man-made—therefore they can be solved by man. And man can be as big as he wants. Kennedy also made two announcements: 1.) that the Soviets had expressed a desire to negotiate a nuclear test ban treaty, and 2.) that the U.S. had postponed planned atmospheric tests. West Berlin speech In 1963, Germany was enduring a time of particular vulnerability due to Soviet