Democrats have a primary in New Hampshire too, and Biden’s not on the ballot
Like most incumbent presidents, Biden appears to have avoided a serious threat to his renomination. His main opponents, Dean Phillips and Marianne Williamson, are extremely unlikely to win the party's nod. However, unlike his recent predecessors (and his major 2024 opponents), Biden didn't file for the New Hampshire ballot because the state's primary date violates the Democratic National Committee's calendar rules for the 2024 cycle, which upset New Hampshire Democrats by threatening their state's long-held spot as the first-in-the-nation primary. Yet many Granite State Democrats are also working to help Biden win as a write-in candidate to avoid allowing one of his fledgling opponents to claim victory. And polls have found Biden comfortably leading the field despite his write-in status, although his support has ranged from about 50 percent to 70 percent.
This isn't an unprecedented situation: In the 1960s, President Lyndon Johnson twice won as a write-in candidate. While New Hampshire's primary has included a presidential preference vote since 1952, the 1964 Democratic ballot didn't have any candidate names in the preference section — Johnson won 95 percent as a write-in. But in 1968, his less-convincing write-in performance had a much bigger impact and likely played a role in his exit from the race. Amid frustration over Johnson's handling of the Vietnam War, Minnesota Sen. Eugene McCarthy challenged him in New Hampshire and, unlike Johnson, put his name on the primary ballot. Johnson fell just short of 50 percent and only won by about 8 points over McCarthy. In the days following the primary, New York Sen. Robert Kennedy jumped into the race, and Johnson soon surprised the country by announcing that he wouldn't seek renomination.
Phillips, who usually polls better than Williamson in New Hampshire, is a long-shot to actually defeat Biden, but McCarthy's 1968 showing looms large as an example of how a sizable vote share in defeat can still count for much. Other past examples of strong incumbent challengers also stand out. In March 1952, Tennessee Sen. Estes Kefauver did the unthinkable by actually defeating President Harry Truman outright in the Democratic primary, 55 percent to 44 percent, which led Truman to announce he wouldn't seek renomination. In February 1976, President Gerald Ford only outdistanced former California Gov. Ronald Reagan by little more than 1 point in New Hampshire and went on to barely edge out Reagan for the GOP nomination. In 1980 and 1992, incumbent presidents Jimmy Carter and George H.W. Bush won their party primaries by 10 and 16 points, respectively, showcasing intraparty divisions that may have contributed to their reelection defeats in November.
—Geoffrey Skelley, 538