The U.S. Chamber of Commerce will back Republican Josh Mandel's challenge to Sen. Sherrod Brown (D) in Ohio.
The endorsement for Mandel, the first-term state treasurer, will come Wednesday at an event in Ohio, according to a spokeswoman for the Chamber.
The official endorsement is essentially a formality, as the Chamber has been attacking Brown on the air since November. Mandel ran unopposed in the GOP primary.
"As a strong advocate for the free-enterprise system, my number one priority in the U.S. Senate will be to help create an environment that allows the private sector to grow and create jobs,” Mandel said in a statement.
Brown spokesman Justin Barasky said the Chamber had spent almost $4 million attacking Brown and accused Mandel's campaign of being dependent on special interests.
- This story was posted at 10:09 a.m. and has been updated.