INDIANAPOLIS (AP) — Republican U.S. Senate candidate Todd Young has been endorsed by the U.S. Chamber of Commerce.

The national business group previously worked closely with the Bloomington congressman’s Democratic rival, former Indiana Sen. Evan Bayh.

But on Monday the group joined Young at a press conference where both attacked Bayh, accusing him of being a threat to the “American free enterprise system.”

Young also personally attacked Bayh calling him a “fundamentally flawed” person who only “looks out for himself.”

Bayh spokesman Ben Ray says the attacks show the Young campaign is desperate. He also says Young’s attack on Bayh is “pretty rich” considering Young took donations from Carrier Corp., which is outsourcing more than 1,000 jobs in Indiana to relocate to Mexico.

The chamber will TV run ads across Indiana supporting Young.