Which of the following men didn't become President upon the death of his predecessor?

Richard M. Nixon was Dwight Eisenhower's Vice President(1953-1961). Eisenhower suffered several serious illnesses during his term; including a serious heart attack in 1955. Eisenhower, however, survived to finish his second term in office. Nixon lost against John F. Kennedy in the 1960 Presidential election. He successfully ran in 1968 and 1972, although he resigned in 1974 during the Watergate Scandal. Eisenhower died during Nixon's first term on March 28, 1969.

Harry S Truman was sworn in as Vice-President under Franklin D Roosevelt on January 20, 1945. He was a compromise candidate at the 1944 Democratic Convention. The incumbent Vice-President, Henry A. Wallace, was considered too far-left for Roosevelt's reelection campaign. Roosevelt, already a sick man, died on April 12, 1945, a few months into his unprecedented fourth term. Truman was thrust into the Oval office.

Calvin Coolidge was sworn in as Vice- President under Warren G. Harding on March 4, 1921. As Governor of Massachusetts, he came into the national spotlight when he acted decisively in the 1919 Boston Police Strike. He became President upon Harding's death on August 2, 1923.

Theodore Roosevelt was sworn in on March 4, 1901 as the Vice-President under President William McKinley. He succeeded into the Presidential office when McKinley was assassinated on September 14, 1901. He was elected President in his own right in 1904. He also ran in 1916 but was unsuccessful.