If you don't mind, I would like to correct you, please. Eisenhower was elected and served for two terms. His Vice-President for both terms was Richard Nixon. Eisenhower followed Truman and John Kennedy followed Eisenhower. Franklin D. Roosevelt was first elected in 1932 and was reelected in 1936, 1940 and 1944 and he died in office in 1945 before WW II was over and Truman became President. Roosevelt was the only President to serve more than two terms.
The 23rd amendment to the constitution was passed in congress in 1947 (during the term of Truman) and approved by enough states in 1951 (during the second term of Eisenhower).
The text of that amendment are: "No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once. But this article shall not apply to any person holding the office of President when this article was proposed by the Congress, and shall not prevent any person who may be holding the office of President, or acting as President, during the term within which this article becomes operative from holding the office of President or acting as President during the remainder of such term."
Professor Concho Bill