This is a list of Democratic Party presidential primaries.
1912
This was the first time that candidates were chosen through primaries. New Jersey Governor Woodrow Wilson ran to become the nominee, and faced the opposition of Speaker of the United States House of Representatives Champ Clark. Wilson defeated Clark and was nominated during the convention. He then won the general election with a landslide victory.
1916
Democratic incumbent President Woodrow Wilson ran for re-election, and faced no major opposition in the primaries.
1920
Former United States Secretary of the Treasury William Gibbs McAdoo and Ohio Governor James Cox were the main candidates. Though William Gibbs McAdoo won a vast majority of states, Cox won the nomination on the 22nd ballot at the convention. Cox went on to lose the election to Republican candidate Warren Harding.
1924
Former United States Secretary of the Treasury William Gibbs McAdoo, 1920 candidate James Cox and Henry Ford were the main candidates. Though McAdoo won a vast majority of states, and well more than half of the popular vote, in those twelve states that held primary elections, it meant little to his performance nationwide. Once at the convention, the party was deadlocked for 102 straight ballots, before dark horse candidate John W. Davis, (who wasn't even a formal candidate when he arrived at the convention) was chosen on the 103rd ballot. Davis went on to lose the election to the Republican candidate, President Calvin Coolidge.
1928
New York Governor Al Smith faced no major opposition in the primaries but lost in the general election against Herbert Hoover.
1932
New York Governor and 1920 vice president candidate Franklin D. Roosevelt ran to become the nominee, and faced the opposition of 1928 candidate Al Smith. Roosevelt easily defeated Smith and was nominated on the fourth ballot, during the convention. He then defeated President Hoover in the general election with a landslide victory.
1936
Democratic incumbent President Franklin D. Roosevelt ran for re-election, and faced no major opposition in the primaries.
1940
Democratic incumbent President Franklin D. Roosevelt ran again for re-election, and faced the opposition of Vice President John Nance Garner in the primaries. Garner lost the primaries and during the convention the vice presidential nomination went to Henry Wallace.
1944
Democratic incumbent President D. Franklin Roosevelt ran again for re-election, and faced no major opposition in the primaries. Senator Harry S Truman of Missouri won the vice presidential nomination on the second ballot, defeating Vice President Wallace.
1948
Democratic incumbent President Harry Truman ran for election to a full term, and faced no major opposition in the primaries.
1952
Senator Estes Kefauver of Tennessee defeated President Truman in the New Hampshire primary, becoming the first person to ever drive an incumbent from the race during the 20th century. Kefauver swept the primaries, but there weren't enough primary delegates to be able to win the nomination. Adlai Stevenson won the nomination but lost against Dwight Eisenhower in the general election.
1956
Adlai Stevenson, who had won the 1952 nomination on third ballot, defeated Estes Kefauver in the early primaries, thus becoming the last losing Democratic presidential nominee to win a second nomination. He would lose the election to President Eisenhower.
1960
Senator John F. Kennedy of Massachusetts defeated Senator Hubert H. Humphrey of Minnesota in the two contested primaries.
1964
Governor George Wallace of Alabama made a feeble challenge to President Lyndon B. Johnson and his surrogates, who were running because he pretended not to be running.
1968
In the last successful challenge to an incumbent President, Senator Eugene J. McCarthy of Minnesota came extremely close to defeating President Johnson in New Hampshire, and with polls showing him winning Wisconsin and the entry of Senator Robert F. Kennedy of New York, the President withdrew from the race.
Thus followed an exciting race between Kennedy and McCarthy, but Vice President Hubert H. Humphrey swept the caucuses and two favorite sons who already endorsed him had won primaries in Ohio and Florida, giving him a substantial lead by the time Senator Kennedy was murdered by Sirhan Sirhan on the day of the California primary.
See also: 1968 United States presidential election 1968 Democratic National Convention