While McGovern said little about his decorated service in World War II, Republicans depicted him as a weak peace activist. At one point, McGovern was forced to defend himself against assertions he had shirked combat.
He'd had enough when a young man at the airport fence in Battle Creek, Mich., taunted that Nixon would clobber him. McGovern leaned in and said quietly: "I've got a secret for you. Kiss my ass." A conservative Senate colleague later told McGovern it was his best line of the campaign.
Defeated by Nixon, McGovern returned to the Senate and pressed there to end the Vietnam War while championing agriculture, anti-hunger and food stamp programs in the United States and food programs abroad. He won re-election to the Senate in 1974, by which point he could make wry jokes about his presidential defeat.
"For many years, I wanted to run for the presidency in the worst possible way — and last year, I sure did," he told a formal press dinner in Washington.
After losing his bid for a fourth Senate term in the 1980 Republican landslide that made Ronald Reagan president, McGovern went on to teach and lecture at universities, and found a liberal political action committee. He made a longshot bid in the 1984 presidential race with a call to end U.S. military involvement in Lebanon and Central America and open arms talks with the Soviets. Former Vice President Walter Mondale won the Democratic nomination and went on to lose to Reagan by an even bigger margin in electoral votes than McGovern had to Nixon.
McGovern talked of running a final time for president in 1992, but decided it was time for somebody younger and with fewer political scars.
After his career in office ended, McGovern served as U.S. ambassador to the Rome-based United Nation's food agencies from 1998 to 2001 and spent his later years working to feed needy children around the world. He and former Republican Sen. Dole collaborated to create an international food for education and child nutrition program, for which they shared the 2008 World Food Prize.
Clinton and his wife, U.S. Secretary of State Hillary Clinton, said in a statement Sunday that while McGovern was "a tireless advocate for human rights and dignity," his greatest passion was helping feed the hungry.
"The programs he created helped feed millions of people, including food stamps in the 1960s and the international school feeding program in the 90's, both of which he co-sponsored with Senator Bob Dole," they said, adding, "We must continue to draw inspiration from his example and build the world he fought for."
McGovern's opposition to armed conflict remained a constant long after he retired. Shortly before Iowa's caucuses in 2004, McGovern endorsed retired Gen. Wesley Clark, and compared his own opposition to the Vietnam War to Clark's criticism of President George W. Bush's decision to wage war in Iraq. One of McGovern's 10 books was 2006's "Out of Iraq: A Practical Plan for Withdrawal Now," which he wrote with William R. Polk.
In early 2002, George and Eleanor McGovern returned to Mitchell, where they helped raise money for a library bearing their names. Eleanor McGovern died there in 2007 at age 85; they had been married 64 years, and had four daughters and a son.
"I don't know what kind of president I would have been, but Eleanor would have been a great first lady," he said after his wife's death in 2007.
One of their daughters, Teresa, was found dead in a Madison, Wis., snowdrift in 1994 after battling alcoholism for years. He recounted her struggle in his 1996 book "Terry," and described the writing of it as "the most painful undertaking in my life." It was briefly a best-seller and he used the proceeds to help set up a treatment center for victims of alcoholism and mental illness in Madison.
Before the 2008 presidential campaign, McGovern endorsed then-Sen. Hillary Clinton for the Democratic nomination but switched to Obama that May. He called the future president "a moderate," cautious in his ways, who wouldn't waste money or do "anything reckless."