1980
The incumbent President Jimmy Carter faced high unemployment, high inflation and gas shortages in California. Against this backdrop, Ted Kennedy decided to run after sitting out 1968, 1972 and 1976. Kennedy stumbled badly in an interview, then the Iran hostage crisis in November 1979 dealt a near fatal blow as Carter's calm approach caused his poll numbers to rise. Carter won decisively everywhere except Massachusetts until the public began to grow weary of the hostage situation. Kennedy then began to win and even swept the last states. It was too little, too late. Carter had a slight advantage and enough delegates to win the nomination.
See also: United States presidential election, 1980#Democratic PartyRead more about this topic: Democratic Party (United States) Presidential Primaries