KANSAS CITY, Mo. (AP) - U.S. Sen. Claire McCaskill says she won't run for Missouri governor in 2016.
The Democrat announced her decision Monday on KCUR radio in Kansas City.
McCaskill's decision clears the path for fellow Democrat and Missouri Attorney General Chris Koster, who already has been running for the state's highest office.
Current Democratic Gov. Jay Nixon is barred by term limits from seeking re-election.
The only declared Republican candidate is former U.S. Attorney and House Speaker Catherine Hanaway, but Missouri Auditor Tom Schweich also has been considering the race. That could mean a potential primary battle for the GOP.
McCaskill ran for governor in 2004, defeating then-Gov. Bob Holden in a Democratic primary. She lost to Republican Matt Blunt in the general election but was elected to the U.S. Senate in 2006.