Brater won election as a Democrat to the Ann Arbor city council from the city's Third Ward in 1988. She then ran for mayor of Ann Arbor in April 1991, defeating two-term incumbent Republican mayor Gerald D. Jernigan.
Brater's victory in the 1988 election for the Ann Arbor city council and her subsequent win over Jernigan in the 1991 mayoral race are both significant events in her political career.