The U.S. Chamber of Commerce, which is expected to spend some $50 million to defend pro-business incumbent in competitive primaries this year, launched a new television ad Friday that offers a preview of how the Republican civil war may play out over the airwaves this spring.

The ad zeroes in one of this cycle’s marquee primary races, which is taking place in Idaho’s Second District, of all places. Interest groups hailing from the GOP’s Establishment wing are going head-to-head against the passel of conservative outside groups. The primary pits incumbent Republican Mike Simpson, a close ally of House Speaker John Boehner, against Bryan Smith, who is backed by organizations like the Club for Growth and FreedomWorks.

The Chamber ad, which harps on Smith’s work as a trial lawyer, is a preview of how Simpson’s allies will try to parry the challenge. Watch it below.

Blair Latoff Holmes, a spokesperson for the Chamber, said the organization’s policy was not to disclose the size of specific ad buys.

Conservative groups vying to oust Simpson, meanwhile, say the eight-term representative is insufficiently conservative. Simpson scored a 47% in the Club for Growth’s 2013 scorecard.

Write to Alex Altman at alex_altman@timemagazine.com.