"My deepest condolences to the family of former Senator Nancy Kassebaum Baker—a trailblazer for women in politics and dedicated public servant," Sen. Marsha Blackburn (R-Tennessee) tweets. "May she rest in peace."

The wife of Sen. Howard Baker Jr. (R-Tennessee), Sen. Nancy Kassebaum Baker (R-Kansas) served from 1978 to 1997, according to the Library of Congress.