CHICAGO (AP) — Former U.S. Sen. Adlai Stevenson III of Illinois has died at his home on Chicago’s North Side. He was 90.

His son, Adlai Stevenson IV, confirmed the Democrat’s death and said his father had dementia. Before his health declined, Stevenson kept active organizing presentations and speakers for the Adlai Stevenson Center on Democracy in Libertyville, Illinois.

He also worked on the family farm in Hanover, Illinois. Stevenson ran for governor of Illinois twice, losing his 1982 run by just 5,074 votes to Republican Gov. Jim Thompson. It is the closest Illinois election for governor in modern state history.