Former President Barack Obama endorsed Illinois Lt. Gov. Juliana Stratton for the U.S. Senate on Tuesday, giving the Democratic nominee a high-profile boost ahead of the November election. Stratton won the Democratic primary in March, defeating U.S. Reps. Raja Krishnamoorthi and Robin Kelly. She is seeking to replace Sen. Dick Durbin, who has served in the Senate for decades. Obama has backed Stratton before. In 2016, while president, he made an uncommon endorsement in a state legislative contest and supported her campaign for an Illinois House seat representing Hyde Park. Obama is expected to campaign in several battleground states before Election Day, but Stratton's campaign told the Chicago Sun-Times he is not expected to appear at her events. The endorsement comes as Illinois voters prepare to choose who will represent the state in the Senate.