“There clearly are people in the Republican Party at the moment for whom the business community and the interests of the business community — the jobs and members they represent — don’t seem to be their top priority,” said Dan Danner, the head of the National Federation of Independent Businesses, which spearheaded opposition to President Obama’s health care law among small businesses. “They don’t really care what the N.F.I.B. thinks, and don’t care what the Chamber thinks, and probably don’t care what the Business Roundtable thinks.”

The lawmakers seem to agree. Representative Randy Neugebauer, Republican of Texas and a Tea Party caucus member, said in an interview on Wednesday that if American corporations wanted to send their money elsewhere, that was their choice.

“We have got to quit worrying about the next election, and start worrying about the country,” said Mr. Neugebauer, who sits on the House Financial Services Committee and is a recipient of significant donations from Wall Street.

Few of the most conservative House lawmakers draw substantial support from business political action committees, and business lobbyists acknowledged that the mere suggestion they were considering backing primary challenges next year could enhance grass-roots support for the very lawmakers they want to defeat. But the dysfunction in Washington has now turned so extreme, they said, that they had few other options.

“What we want is a conservative business person, but someone who in many respects will be more realistic, in our opinion,” said Bruce Josten, the top lobbyist at the U.S. Chamber of Commerce, the single biggest lobbying organization in Washington.

In the two previous battles over the debt limit, many chief executives were reluctant to take sides, banding together in groups like Fix the Debt, which spent millions of dollars on a campaign urging Democrats and Republicans to work toward a “grand bargain” on the budget. But with shutdown a reality, and the clock ticking toward default, some of those same executives now place the blame squarely on conservative Republicans in the House.