ATLANTA (AP) — Georgia's Democratic labor commissioner is running to unseat Republican U.S. Senator Johnny Isakson in this fall's election.

Michael Thurmond is one of the most prominent black Democrats in a state that has increasingly voted Republican in recent years. He announced his campaign Wednesday.

Thurmond's primary opponent in July is a former county employee who has never held elected office.

The winner will face an uphill fight against Isakson, who has more than $4 million in the bank for his re-election bid.

Thurmond has served three terms as labor commissioner. Before that he was a state lawmaker and head of the state's Department of Family and Children's Services.

Isakson recently returned to the campaign trail after being hospitalized for a bacterial infection and an irregular heartbeat.