Former US senator George McGovern, a liberal icon who vowed to end the Vietnam War but lost a landslide presidential election to Richard Nixon in 1972, has died at the age of 90.
McGovern died at about 5:15 am (22:15 NZT) at the Dougherty Hospice House in Sioux Falls, South Dakota, surrounded by relatives and friends, his family said in a statement.
The three-term senator, a former World War II bomber pilot, was credited with bringing women, youths and minorities into the Democratic Party in a broad-based White House campaign that foundered after revelations of his running mate's battle with mental illness.
"We are blessed to know that our father lived a long, successful and productive life advocating for the hungry, being a progressive voice for millions and fighting for peace," the family statement read.
President Barack Obama praised McGovern as a man who "dedicated his life to serving the country he loved" and as "a statesman of great conscience and conviction."
Vice President Joe Biden said he was "honoured" to serve with McGovern in the US Senate "and to call him a friend."
And, in a joint statement, former president Bill Clinton and his wife Hillary, currently serving as secretary of state, said McGovern "always worked to advance the common good and help others realise their potential.
"Of all his passions," the Clintons said, "he was most committed to feeding the hungry, at home and around the world."
McGovern's legacy even drew praise from Republican former House speaker Newt Gingrich, who said he had "a very good sense of humour" and was "just a great guy."
The 1972 presidential bid
McGovern's 1972 campaign, which harnessed growing opposition to the Vietnam War, was built on a grassroots movement that expanded the Democratic Party from its base among the urban white workers and unions to women, minorities and student activists - the core of today's party.
Both Bill and Hillary Clinton entered politics while working for the campaign when they were in their mid-20s, and many McGovern supporters returned the favor during Hillary's primary battle with Barack Obama in 2008.
The campaign however suffered a fatal blow when McGovern's running mate, Missouri Senator Thomas Eagleton, was forced to quit the ticket after it emerged that he had been hospitalised on three occasions and given electroshock therapy.
McGovern had not known about Eagleton's history of depression, which in part explains why candidates now typically conduct exhaustive background checks on prospective running mates.
McGovern lost to Nixon in one of the most dramatic landslides in US history, winning only Massachusetts and the District of Columbia. The term "McGovern liberal" became a favourite taunt of Republicans for decades.
Nixon went on to end direct US military involvement in Vietnam with the signing of the Paris Peace Accords in January 1973. However Nixon was forced to resign two years later in the infamous Watergate scandal, named for the burglary of McGovern's party headquarters less than five months before his election defeat.
Born on July 19, 1922 in Avon, South Dakota, McGovern enlisted in the US Army Air Corps at the age of 19 and flew 35 missions as a B-24 bomber pilot in Europe during World War II. He later earned a PhD in history from Northwestern University in 1953.
McGovern served in the US House of Representatives from 1957 to 1961, and as special assistant in charge of the Food for Peace Program under president John F. Kennedy in 1961.
He was elected to the US Senate the following year, eventually serving three six-year terms and championing the fight against world hunger.
After leaving the Senate in 1981, McGovern served as a visiting professor at several universities and was president of the Middle East Policy Council, a Washington-based think tank, in the 1990s.
In 1994, his daughter Terry, a mother of two who had long suffered from alcoholism, froze to death when she passed out in a Wisconsin snowbank.
McGovern later wrote a book about Terry's struggle with substance abuse and used the proceeds to build a treatment center for alcoholic women and children.
He had four other children with Eleanor, his wife of 63 years, who died in 2007.
From 1998 to 2001, McGovern served as US ambassador to the UN Food and Agricultural Organization in Rome. Then-president Clinton awarded him the Presidential Medal of Freedom in August 2000.
McGovern lamented his 1972 defeat in a Washington Post op-ed last month, saying: "I wanted to win for our party, our young soldiers, and the men and women of goodwill disaffected by Watergate and turned off by the power of big money in politics."
But "at the wise old age of 90, I can say that losing the presidency was one chapter in a long, complex and richly happy life in which I learned that you can't always control all the outcomes."