Former Minnesota Attorney General and gubernatorial candidate Warren Spannaus, known for pushing Minnesota's landmark gun-control law and for his longtime friendship and professional partnership with former Vice President Walter Mondale, died suddenly Monday. He was 86.

Spannaus was elected attorney general in 1970 and re-elected twice, serving from 1971 to 1983. He ran for governor in 1982, received the DFL Party endorsement, but lost the primary to eventual winner Rudy Perpich.

In 1975, Spannaus pushed the state's landmark gun law requiring waiting periods and background checks. Gun-control opponents made him a target, circulating pictures of his face behind a bull's-eye. They created bumper stickers with the slogan "Dump Spannaus" when he ran for governor.

"They didn't forget him," Mondale said Monday of his friend and DFL ally of more than 50 years.

"He accepted that."

After losing the gubernatorial race, Spannaus never held elected office again. In an interview with the Star Tribune in 2013, Spannaus said of his gun-control advocacy, "I never regretted that."

Spannaus said his law applied only to handguns and that he was falsely accused of restricting rifles and shotguns. Spannaus said during the interview that the NRA continued to misrepresent the issue and "bully the people in Congress."

After his elective political career ended, Spannaus joined the Minneapolis-based Dorsey & Whitney law firm, where he worked as a lobbyist. He worked there alongside Mondale and current U.S. Sen. Amy Klobuchar, who said Spannaus was a mentor who hired her as an intern in the attorney general's office.

Mondale said Spannaus' work on educating the public about guns was "a noble chapter" in state history. "He took it on when most people wouldn't touch it," Mondale said.

When he was working on the legislation, Mondale said, Spannaus always accepted the invitations to go speak at gun clubs where 300 to 400 people would show up. He probably didn't change their minds, but they'd leave thinking he was a good guy, Mondale said.

The former vice president was state attorney general when Gov. Wendell Anderson introduced him to Spannaus and suggested he wouldn't regret hiring him. "We've been close ever since," Mondale said.

Klobuchar said, "The largest lesson I learned from Warren is that when you get into politics, you never forget where you came from."

Spannaus would rest his shoes, often with holes in the soles, on his desk during conversations or take out some polish to shine them up himself.

"He was a taxi driver that became the attorney general," she said.

When he worked in the tony downtown Minneapolis office of Dorsey, a disabled man he'd known for years and had helped while attorney general would sometimes stop in. Spannaus would give him lunch money — just as he had done for decades. He went to everyone's funeral and everyone's wedding, Klobuchar said.

When the university's law school was named for Mondale, the vice president made sure Spannaus got his due with his name on the student lounge. Klobuchar said she and Spannaus went there to have lunch recently and she let the students know who he was. "I'd say, 'Get your feet off the table; this room is named for this man,' " she said.

Spannaus delighted in pointing out his signature hires such as state Supreme Court Justice Sandra Gardebring. "I hired her first," he'd say, according to Klobuchar.

Although Spannaus had been fighting cancer, Mondale said friends and family thought he was over the worst of it, but he had been in the hospital recently and died there early Monday.

Spannaus was born in St. Paul on Dec. 5, 1930. He served in the U.S. Navy from 1951 to 1954 before attending college and law school at the U. He was a special assistant in the state attorney general's office from 1963 to 1965 before joining Mondale's U.S. Senate staff. He was chairman of the DFL State Central Committee from 1967 to 69.

Commemorations rolled in along with condolences for his family.

Minnesota DFL Party Chairman Ken Martin said that, as the leader of the state DFL, Spannaus "fought tirelessly" to unite the party during the Vietnam War era. "His effective leadership catapulted the DFL from the brink of destruction and on track to becoming the strong, productive party it is today," Martin said, describing him as a "giant of Minnesota politics."

Gov. Mark Dayton, also a DFLer, called him a champion for the best interests of Minnesotans who expanded the attorney general's role in safeguarding consumers and protecting natural resources.

Lt. Gov. Tina Smith said: "As a private citizen, Warren was compassionate and generous with his time, helping to improve conditions for individuals with mental illness and developmental disabilities."

Longtime media and political consultant D.J. Leary said: "He was an extraordinary man. More than that he was an extraordinary public servant. He was a good friend to so many people."

Leary spoke of the bond between Spannaus and Mondale. "He was his right arm," Leary said. "They had a marvelous friendship."

Spannaus is survived by his wife, Marjorie Clarkson. The couple had three children, Christine, David and Laura, and several grandchildren. A service was tentatively scheduled for Monday.

Twitter: @rochelleolson