"I think it was my study of history that convinced me that the Democratic Party was more on the side of the average American," he said.
In the early 1950s, Democrats held no major offices in South Dakota and only a handful of legislative seats. McGovern, who had gotten into Democratic politics as a campaign volunteer, left teaching in 1953 to become executive secretary of the South Dakota Democratic Party. Three years later, he won an upset election to the House; he served two terms and left to run for Senate.
Challenging conservative Republican Sen. Karl Mundt in 1960, he lost what he called his "worst campaign." He said later that he'd hated Mundt so much that he lost his sense of balance.
President John F. Kennedy named McGovern head of the Food for Peace program, which sends U.S. commodities to deprived areas around the world. He made a second Senate bid in 1962, unseating Sen. Joe Bottum by just 597 votes. He was the first Democrat elected to the U.S. Senate from South Dakota since 1930.
In his first year in office, McGovern took to the Senate floor to say that the Vietnam War was a trap that would haunt the United States — a speech that drew little notice. He voted the following August in favor of the Gulf of Tonkin resolution under which President Lyndon B. Johnson escalated the U.S. war in the southeast Asian nation.
While McGovern continued to vote to pay for the war, he did so while speaking against it. As the war escalated, so did his opposition. Late in 1969, McGovern called for a cease-fire in Vietnam and the withdrawal of all U.S. troops within a year. He later co-sponsored a Senate amendment to cut off appropriations for the war by the end of 1971. It failed, but not before McGovern had taken the floor to declare "this chamber reeks of blood" and to demand an end to "this damnable war."
McGovern first sought the Democratic presidential nomination late in the 1968 campaign, saying he would take up the cause of the assassinated Sen. Robert F. Kennedy. He finished far behind Vice President Hubert H. Humphrey, who won the nomination, and Minnesota Sen. Eugene McCarthy, who had led the anti-war challenge to Johnson in the primaries earlier in the year. McGovern later called his bid an "anti-organization" effort against the Humphrey steamroller.
"At least I have precluded the possibility of peaking too early," McGovern quipped at the time.
The following year, McGovern led a Democratic Party reform commission that took power previously held by party leaders and bosses at the national conventions and gave it to voters instead. The result was the system of presidential primary elections and caucuses that now selects the Democratic and Republican presidential nominees.
In 1972, McGovern ran under the rules he had helped write. Initially considered a longshot against Sen. Edmund S. Muskie of Maine, McGovern built a bottom-up campaign organization and went to the Democratic national convention in command. He was the first candidate to gain a nominating majority in the primaries before the convention.
It was a meeting filled with intramural wrangling and speeches that verged on filibusters. By the time McGovern delivered his climactic speech accepting the nomination, it was 2:48 a.m., and with most of America asleep, he lost his last and best chance to make his case to a nationwide audience.
Before selecting Eagleton, McGovern did not know of his running mate's mental health woes and, after dropping him from the ticket, he struggled to find a replacement. Several Democrats said no, and a joke made the rounds that there was a signup sheet in the Senate cloakroom. Shriver, a member of the Kennedy family, finally agreed.
The campaign limped into the fall on a platform advocating withdrawal from Vietnam in exchange for the release of POWs, cutting defense spending by a third and establishing an income floor for all Americans. McGovern had dropped an early proposal to give every American $1,000 a year, but the Republicans continued to ridicule it as "the demogrant." They painted McGovern as an extreme leftist and Democrats as the party of "amnesty, abortion and acid."