Josh Green examines the rift between the GOP and the U.S. Chamber of Commerce, a major GOP donor:

On Oct. 1, House Republicans ignored the Chamber’s pleas to keep the government running. The shutdown is costing the U.S. economy $300 million a day, according to IHS (IHS), a global market-research firm, and it’s only the latest sign suggesting that the old adage, “Republicans are the party of business,” no longer holds true. From the austerity imposed by sequestration to the refusal to reform immigration laws to the shutdown and now, as appears likely, another debt-ceiling showdown when U.S. borrowing authority expires on Oct. 17, the GOP’s actions have put a strain on one of its most valuable partners: the business community.

Drezner asks, “given the Chamber of Commerce’s tilt, why aren’t GOP representatives listening more closely?” Larison’s answer:

Because the Chamber of Commerce leans so heavily towards the GOP, Republican politicians may conclude that they can ignore some of its complaints without provoking the group to shift more of its support to the other party. Consistently and overwhelmingly favoring one party over another signals to party leaders that your group’s concerns can be dismissed more easily when the leaders have other priorities. The Chamber’s support for Republicans is being taken for granted because that support is so lopsided in the GOP’s favor, and as a result it sometimes has much less influence with what the party does in Congress than one would expect.