Former Senator Adlai Stevenson the 3rd is dead at the age of 90. The Illinois Democrat passed away Monday at his Chicago home following a battle with dementia. Stevenson was the great grandson of former Vice President Adlai Stevenson and the son of former Illinois Governor Adlai Stevenson the 2nd. He ran for Illinois governor twice, including a narrow 1982 loss to James R. Thompson. Stevenson also served in the state House of Representatives and a term as state treasurer before representing the state of Illinois in the U.S. Senate from 1970 until 1981.