Sensing that the time might be right to take back the White House, a large field of Democratic candidates for President emerged. The favorite of the party establishment was Senator Edmund Muskie of Maine. Muskie was seen as a moderate who had been the 1968 Democratic candidate for vice-president on a ticket with Hubert Humphrey. He had performed well in that role, and in August of 1971 Harris polling reported numbers supporting a Muskie victory over the incumbent Nixon if the election had been held that day.
An interesting feature of this campaign was the candidacy of Shirley Chisholm, a member of the US House of Representatives from New York. She announced that she would seek her party's nomination for President, making her the first African-American ever to seek the nomination for president for a major party and the first woman to run for the Democratic presidential nomination. Her campaign slogan was "Unbought and Unbossed", stressing her independence.
The Iowa caucus was held first on January 24. Edmund Muskie won 35.5% support, George McGovern 22.6% and 35.8% of delegates were uncommitted. It looked as if Muskie's plan to win the nomination and the presidency was unfolding according to plan. But then came the New Hampshire primary, and something called the "Canuck Letter". This was a letter that was published in the Manchester Union-Leader. The Canuck letter was a forged letter to the editor of the Manchester Union Leader, published February 24, 1972, two weeks before the New Hampshire primary vote. The gist of the letter was that Senator Muskie was prejudiced against Americans of French-Canadian descent, a sizeable demographic in the north-west region at the time.
The letter was later determined to be the sabotage work of Donald Segretti and Ken W. Clawson, member of Richard Nixon's "dirty tricks squad". It was writtem in a childish scrawl with poor spelling. The author of the Canuck letter claimed to have met Muskie and his staff in Florida, and to have asked Muskie how he could understand the problems of African Americans when his home state of Maine has such a small black population. According to the letter, a member of Muskie's staff was said to have responded, "Not blacks, but we have Canucks" (which the letter spelled as "Cannocks"). The author further claimed that Muskie was present when the remark was made and laughed at it. Although the term in an innocuous one today, with many Canadians using it to describe themselves (the Vancouver NHL hockey franchise even bears that name), the term "Canuck" was considered derogatory among those Americans of French-Canadian ancestry who lived in New England. This was a significant number of New Hampshire voters at that time.
It was only much later, on October 10, 1972, FBI investigators revealed that the Canuck letter was part of a dirty tricks campaign against Democrats orchestrated by the Committee to Re-Elect the President (CRP), but even then, this fact was not made public. The letter would indirectly contribute to the implosion of Muskie's candidacy.
Subsequently, the paper published an attack on the character of Muskie's wife Jane, reporting that she drank and used off-color language. On the morning of February 26, two Saturdays before the March 7 primary, Muskie delivered a speech in front of the offices of the Union Leader, calling its publisher, William Loeb, a liar. Muskie attached Loeb for impugning the character of Muskie's wife, Jane. Newspapers reported that Muskie cried openly. David Broder of The Washington Post wrote that Muskie "broke down three times in as many minutes". David Nyhan of The Boston Globe reported Muskie "weeping silently". Muskie acknowledged that his voice cracked, but claimed that it cracked from anger. Muskie had an antagonistic relationship with Loeb, who had referred to Miskie in the 1968 election as "Moscow Muskie", and called him a flip-flopper. Muskie claimed his tears were actually snow melting on his face. Muskie made an emotional defense of his wife in the speech, which did take place during a snowstorm. Here is a video of Muskie's remarks. From this video, it seems as if reports of his crying are exaggerated:
New Hampshire voters took Muskie's emotional reaction as a sign of weakness. Muskie did worse than expected in the primary. Although he won the primary, Muskie's winning margin of 46% to McGovern's 37%, was smaller than his campaign had predicted. The second-place finish gave the McGovern campaign a boast of its momentum. He won the Illinois Primary as well as the caucuses in his home state of Maine, but that was it. McGovern won subsequent contests in Wisconsin and Massachusetts, races that Muskie was expected to win. Alabama governor George Wallace did well in the South, winning every county in the Florida primary with the exception of Miami-Dade. Later in the year, Wallace was shot while campaigning, and left paralyzed in an assassination attempt by Arthur Bremer. The Nixon campaign attempted to plant McGovern campaign literature in Bremer's apartment as a means to drive Wallace supporters away from the Democratic Party. Wallace won the Maryland primary and the Michigan primary both held the following day (May 16th), but the assassination attempt effectively ended his campaign.
McGovern succeeded in winning the nomination by winning primaries through grass-roots support in spite of establishment opposition. He had led a commission to redesign the Democratic nomination system after the messy and confused nomination struggle and convention of 1968. The fundamental principle of the McGovern-Fraser Commission was that the Democratic primaries should determine the winner of the Democratic nomination. However, the new rules angered many prominent Democrats whose influence was marginalized, and those politicians refused to support McGovern's campaign, leaving the McGovern campaign at a significant disadvantage in funding compared to Nixon.