1945-2000 By quriedavenport Feb 27, 1951 22nd Amendement to the Constitution is ratified, limiting the president to two terms Sep 4, 1951 President Truman speaks in first coast-to-coast live television broadcast Jul 25, 1952 Puerto Rico becomes a U.S. commonwealth Nov 1, 1952 First hydrogen bomb is detonated by the U.S. on Eniwetok, an atoll in the Marshall Islands Jan 20, 1953 Dwight Eisenhower is inaugurated as the 34th president Jun 19, 1953 Julius and Ethel Rosenberg are executed for passing secret information about U.S. atomic weaponry to the Soviets Apr 22, 1954 Sen. Joseph R. McCarthy accuses army officials, members of the media, and other public figures of being Communists during highly publicized hearings May 17, 1954 Brown v. Board of Education of Topeka, Kans.: Landmark Supreme Court decision declares that racial segregation in schools is unconstitutional Jan 21, 1957 Eisenhower's second inauguration Sep 24, 1957 President sends federal troops to Central High School in Little Rock, Ark., to enforce integration of black students Jan 31, 1958 Explorer I, first American satellite, is launched Jan 3, 1959 Alaska becomes the 49th state Aug 21, 1959 Hawaii becomes the 50th state Jan 3, 1961 U.S. severs diplomatic relations with Cuba