SPRINGFIELD, Ill. (AP) — A union lobbyist who worked just one day as a substitute teacher is entitled to a pension worth potentially tens of thousands of dollars annually, the state Supreme Court ruled Thursday in an opinion reinforcing its position that retirement benefits promised to public workers can't be "diminished or impaired." The 4-3 decision affected just one member of the Teachers' Retirement System but solidified the high court's previous finding that public-pension benefits are guaranteed under the state constitution.