In 1951, the United States ratified the 22nd Amendment, making a president ineligible for election to a third term or for election to a second full term after serving more than two remaining years of a term of a previously elected president.
The latter clause did not apply to Truman's situation in 1952 because of a grandfather clause excluding the amendment's application to the incumbent president.

Therefore, he seriously considered running for another term in 1952, and left his name on the ballot in the New Hampshire primary.
However all his close advisors, pointing to his age, his failing abilities, and his poor showing in the polls, talked him out of it.
At the time of the 1952 New Hampshire primary, no candidate had won Truman's backing.
His first choice, Chief Justice Fred M. Vinson, had declined to run; Illinois Governor Adlai Stevenson had also turned Truman down, Vice President Barkley was considered too old, and Truman distrusted and disliked Senator Kefauver, who had made a name for himself by his investigations of the Truman administration scandals.

Truman had hoped to recruit General Eisenhower as a Democratic candidate, but found him more interested in seeking the Republican nomination.
Accordingly, Truman let his name be entered in the New Hampshire primary by supporters.
The highly unpopular Truman was handily defeated by Kefauver; 18 days later the president formally announced he would not seek a second full term.
Truman was eventually able to persuade Stevenson to run, and the governor gained the nomination at the 1952 Democratic National Convention.

Eisenhower gained the Republican nomination, with Senator Nixon as his running mate, and campaigned against what he denounced as Truman's failures: "Korea, communism and corruption".
He pledged to clean up the "mess in Washington," and promised to "go to Korea."
Eisenhower defeated Stevenson decisively in the general election, ending 20 years of Democratic presidents.
While Truman and Eisenhower had previously been on good terms, Truman felt annoyed Eisenhower did not denounce Joseph McCarthy during the campaign.
Similarly, Eisenhower was outraged when Truman accused the former general of disregarding "sinister forces ... Anti-Semitism, anti-Catholicism, and anti-foreignism" within the Republican Party.
In 1951, the United States ratified the 22nd Amendment, making a president ineligible for election to a third term or for election to a second full term after serving more than two remaining years of a term of a previously elected president. The latter clause did not apply to Truman's situation in 1952 because of a grandfather clause excluding the amendment's application to the incumbent president.
Therefore, he seriously considered running for another term in 1952, and left his name on the ballot in the New Hampshire primary. However all his close advisors, pointing to his age, his failing abilities, and his poor showing in the polls, talked him out of it. At the time of the 1952 New Hampshire primary, no candidate had won Truman's backing. His first choice, Chief Justice Fred M. Vinson, had declined to run; Illinois Governor Adlai Stevenson had also turned Truman down, Vice President Barkley was considered too old, and Truman distrusted and disliked Senator Kefauver, who had made a name for himself by his investigations of the Truman administration scandals.
Truman had hoped to recruit General Eisenhower as a Democratic candidate, but found him more interested in seeking the Republican nomination. Accordingly, Truman let his name be entered in the New Hampshire primary by supporters. The highly unpopular Truman was handily defeated by Kefauver; 18 days later the president formally announced he would not seek a second full term. Truman was eventually able to persuade Stevenson to run, and the governor gained the nomination at the 1952 Democratic National Convention.
Eisenhower gained the Republican nomination, with Senator Nixon as his running mate, and campaigned against what he denounced as Truman's failures: "Korea, communism and corruption". He pledged to clean up the "mess in Washington," and promised to "go to Korea." Eisenhower defeated Stevenson decisively in the general election, ending 20 years of Democratic presidents. While Truman and Eisenhower had previously been on good terms, Truman felt annoyed Eisenhower did not denounce Joseph McCarthy during the campaign. Similarly, Eisenhower was outraged when Truman accused the former general of disregarding "sinister forces ... Anti-Semitism, anti-Catholicism, and anti-foreignism" within the Republican Party.
Harry S. Truman