New Hampshire has held a presidential primary since 1916 and started the tradition of being the first presidential primary in the United States starting in 1920. Until 1948, the New Hampshire primary, like most of the small number of other primaries in the country, listed only the names of local citizens who wanted to be delegates to the state convention. In 1948, Richard F. Upton, speaker of the New Hampshire House of Representatives decided to make the primary "more interesting and meaningful…so there would be a greater turnout at the polls." The state legislature passed a law allowing citizens to vote directly for the presidential candidates. Any candidate could get on the ballot if he submitted fifty supporting petitions from each of the two congressional districts, and voters could choose delegates who were explicitly pledged to a particular candidate.
The winner in New Hampshire has not always gone on to win their party's nomination, as demonstrated by Republicans Leonard Wood in 1920, Harold Stassen in 1948 , Henry Cabot Lodge, Jr. as a write-in candidate in 1964, Pat Buchanan in 1996, and John McCain in 2000, and Democrats Estes Kefauver in 1952 and 1956, Paul Tsongas in 1992, Hillary Clinton in 2008, and Bernie Sanders in 2016.
The New Hampshire primary is the first in a series of nationwide party primary elections and the second party contest (the first being the Iowa caucuses) held in the United States every four years as part of the process of choosing the delegates to the Democratic and Republican national conventions which choose the party nominees for the presidential elections to be held the subsequent November. Although only a few delegates are chosen in the New Hampshire primary, its real importance comes from the massive media coverage it receives (along with the first caucus in Iowa). Spurred by the events of the 1968 election, reforms that began with the 1972 election elevated the two states' importance to the overall election, and began to receive as much media attention as all of the other state contests combined. Examples of this extraordinary coverage have been seen on the campuses of Dartmouth College and Saint Anselm College, as the colleges have held multiple national debates and have attracted media outlets like NPR, Fox News, CNN, NBC, and ABC. The publicity and momentum can be enormous from a decisive win by a frontrunner, or better-than-expected result in the New Hampshire primary. The upset or weak showing by a front-runner changes the calculus of national politics in a matter of hours, as happened in 1952 (D), 1968 (D), 1980 (R), and 2008 (D).
In November 1967, Eugene McCarthy declared, "there comes a time when an honorable man simply has to raise the flag" to gauge the country's response and conduct a candidacy for the presidency of the United States by entering the New Hampshire Democratic primary. On March 12, 1968, McCarthy, who was the only candidate on the ballot, came within 7 percentage points of defeating President Lyndon Johnson, a write-in candidate who was technically still exploring his candidacy and had not bothered to file. Just a few days later, on March 16, 1968, Robert F. Kennedy announced he was entering the race for President. Johnson subsequently withdrew from the election with this Shermanesque statement: "I shall not seek, and will not accept, the nomination of my party for another term as your president."
In 1968, the sitting Vice President Hubert Humphrey won the Democratic Vice-presidential primary, and then later won the Presidential nomination after the sitting President Lyndon B. Johnson dropped out of the race.
New Hampshire did not begin to assume its current importance until 1952. In that year, Dwight D. Eisenhower demonstrated his broad voter appeal by defeating Robert A. Taft, "Mr. Republican", who had been favored for the nomination, and Estes Kefauver defeated incumbent President Harry S. Truman, leading Truman to abandon his campaign for a second term of his own. The other president to be forced out of the running for re-election by New Hampshire voters was Lyndon Johnson, who, as a write-in candidate, managed only a 49-42 percent victory over Eugene McCarthy in 1968 (and won fewer delegates than McCarthy), and consequently withdrew from the race.
Before the Iowa caucus first received national attention in the 1970s (Republicans began caucusing in Iowa in 1976), the New Hampshire primary was the first binding indication of which presidential candidate would receive the party nomination. In defense of their primary, voters of New Hampshire have tended to downplay the importance of the Iowa caucus. "The people of Iowa pick corn, the people of New Hampshire pick presidents," said then-Governor John H. Sununu in 1988.
From 1952 to 1988, the person elected president had always carried the primary, but Bill Clinton broke the pattern in 1992, as did George W. Bush in 2000, and Barack Obama in 2008. In 1992, Clinton lost to Paul Tsongas in New Hampshire; in 2000, George W. Bush lost to John McCain in New Hampshire; and in 2008 Barack Obama lost to Hillary Clinton.
Recently, media expectations for the New Hampshire primary have come to be almost as important as the results themselves; meeting or beating expectations can provide a candidate with national attention, often leading to an infusion of donations to a campaign that has spent most of its reserves. For example, in 1992, Bill Clinton, although he did not win, did surprisingly well, with his team dubbing him the "Comeback Kid"; the extra media attention helped his campaign's visibility in later primaries.
New Hampshire's status as the first in the nation is somewhat controversial because the ethnic makeup of the state is not diverse and not representative of the country's voters. This is shown in the 2010 Census data, with the percentage of minority residents being nearly five times smaller than the national average (New Hampshire is 92% non-Hispanic white, versus 64% nationally). Politically however, the state does offer a wide sampling of different types of voters. Although it is a New England state, it is not as liberal as some of its neighbors. For example, according to one exit poll, of those who participated in the 2004 Democratic primary, 4-in-10 voters were independents, and just over 50% said they considered themselves "liberal". Additionally, as of 2002, 25.6% of New Hampshire residents are registered Democrats and 36.7% are Republicans, with 37.7% of New Hampshire voters registered as "undeclared" independents. Also, New Hampshire was the only state in the Northeast to vote for George W. Bush in 2000. This plurality of independents is a major reason why New Hampshire is considered a swing state in general U.S. presidential elections.
New Hampshire's political importance as the first-in-the-nation primary state is highlighted in the documentary film Winning New Hampshire. The film focuses on John Kerry's comeback in 2004 and the decisive effect of the New Hampshire primary on the presidential selection process.
The only time a non-incumbent won the Vice-presidential primary and then went on to be formally nominated by his or her party was in 2004, when Democratic U.S. Senator John Edwards won as a write-in candidate. Edwards, who was running for President at the time, did not actively solicit Vice-presidential votes.
New Hampshire's first-in-the-nation primary status was threatened in 2007, when both the Republican and Democratic National Committees moved to give more populous states a bigger influence in the presidential race.
A Vice-presidential preference primary was also formerly held at the New Hampshire primary. New Hampshire State Senator Jack Barnes, who won the 2008 Republican contest, co-sponsored a bill in 2009 which would eliminate the Vice-presidential preference ballot. The bill passed both houses of the state legislature and took effect in 2012.