Former presidential nominee and Sen. George McGovern in this January, 2011 photo. McGovern passed away Sunday at 90 years old. (Cliff Owen-Pool/Getty Images)

Former presidential challenger George McGovern, who was a U.S. senator for two decades, died in hospice care in South Dakota after dealing with complications of non-Hodgkin lymphoma. He was 90 years old.

He died early Sunday, and the cause of death was not confirmed, reported The Associated Press.

“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,” his family said in a statement obtained by AP. “He continued giving speeches, writing, and advising all the way up to and past his 90th birthday, which he celebrated this summer.”

McGovern, who was a South Dakota senator from 1963 to 1981, was the Democratic Party’s presidential nominee in 1972 against Republican President Richard Nixon.

President Barack Obama said in a statement Sunday, “George McGovern dedicated his life to serving the country he loved,” according to The Washington Post.

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