St. Louis ? Former U.S. Sen. Thomas Eagleton, who resigned as a vice presidential nominee in 1972 after it was revealed he had been hospitalized for depression, died Sunday, according to the office of Sen. Claire McCaskill.

The cause of death was not disclosed. Eagleton, 77, had suffered from a variety of illnesses and ailments in recent years.

“Today Missouri has a hole in its heart,” McCaskill said in a statement. “Tom Eagleton managed to be a statesman, an intellectual and a man of the people all at the same time.”

Eagleton served in the Senate representing Missouri from December 1968 through January 1987.

He was George McGovern’s vice presidential nominee in 1972, but dropped out after it was revealed that he had been hospitalized for psychiatric treatment and had twice undergone electroshock therapy for depression. McGovern chose Sargent Shriver to replace Eagleton and lost to Richard Nixon in the general election.

Eagleton was born in St. Louis in 1929, the son of noted civil trial attorney Mark Eagleton, who once ran unsuccessfully for mayor and encouraged his son’s interest in politics.

Thomas Eagleton was elected circuit attorney at age 26 in 1956, the youngest man ever elected to the position.

He was elected Missouri attorney general in 1960 and lieutenant governor in 1964 before winning election to the U.S. Senate.

Eagleton was considered liberal, but he criticized busing to achieve school desegregation and, as a practicing Roman Catholic, strongly opposed abortion.

Eagleton told The Associated Press in 2003 that he had no regrets.

“Being vice president ain’t all that much,” he said. “My ambition, since my senior year in high school, was to be a senator. Not everybody achieves their ambition. I got to the level that I really had no great right to claim.”

He said he had not had any symptoms of depression for years and “didn’t think it was all that big a deal.”

Eagleton is survived by his wife, Barbara Ann Smith Eagleton, whom he married in 1956, a son and a daughter.