The U.S. Chamber of Commerce is going on the air to rip Rep. Mike Simpson's (R-Idaho) Tea Party opponent for his work as a trial lawyer.
This is the Chamber's first ad attacking Smith in the district. Their earlier ads had been positive spots touting Simpson's record.
Simpson, a close ally of House Speaker John Boehner (R-Ohio), is one of just a few Republican incumbents facing a real challenge from a Tea Party opponent. The Chamber's ad buy shows they are making it a top priority to keep him in office.
Smith's campaign fired back.
"This is just more proof that Idahoans are ready to send a real conservative to Washington in Bryan Smith. Mike Simpson's liberal record of supporting higher taxes, more spending, and even funding ACORN has finally caught up with him," said Smith Campaign Manager Carrie Brown.
Smith is the only House candidate challenging an incumbent who has the backing of the deep-pocketed Club for Growth, but Simpson has been the beneficiary of a renewed push by establishment Republican groups like the Chamber to fight back against the Tea Party. The race is a test of whether that effort will work.
This post was updated at 3:15 p.m.