Tea Party renegades can comfortably ignore public opinion over the government shutdown and debt ceiling fight, the thinking goes, because they are ensconced in non-competitive, gerrymandered districts.

Yet as the shutdown dragged on, and a once-unthinkable debt ceiling default became more likely, the Tea Party began to lose the support of a once powerful ally: Big business. It has reached the point where some business interests are openly floating the idea of supporting more reasonable, business-friendly candidates in primary election challenges to Tea Party-aligned lawmakers.

"We have come to the conclusion that sitting on the sidelines is not good enough," David French, the head lobbyist at the National Retail Federation, told the New York Times.

The business community was already miffed with the Tea Party's tactics ahead of the government shutdown. The powerful U.S. Chamber of Commerce, along with some 250 allied groups, sent a joint letter to Congress on the eve of the shutdown urging recalcitrant Republicans to back down lest they push the economy into free-fall.

With the shutdown now in full effect, business interests are beginning to get behind primary campaigns in at least four districts to unseat candidates who have run roughshod over the GOP leadership, according to the Washington Post's Phillip Rucker. In Michigan, "patience is running low" with sophomore GOP Rep. Justin Amash, who has bucked party leadership many times before.

Amash will likely face a primary challenge next year from a well-heeled businessman, Brian Ellis, according to the Detroit News.

Ellis, meanwhile, has been promised all the money he'll need from "a group of people who can give at robust levels," according to one prominent west Michigan executive. Translation: The leading business and political names in Grand Rapids are backing Ellis' bid, which he's expected to announce formally next month. [Detroit News]

It's an interesting twist on a tactic the Tea Party once used to great effect. Whereas Tea Party uprisings helped unseat longtime Republicans in divisive primary campaigns in 2010 and 2012, establishment Republicans are now trying to return the favor.

The businesses community, upset with its dwindling influence with the party, could use primary campaigns to reassert its power by boosting "more realistic" candidates, as the Chamber of Commerce's top lobbyist, Bruce Josten, put it to the Times.

The Chamber spent $31 million in the last election cycle alone, almost all of it to promote Republican candidates. It certainly has the money to bankroll insurgent campaigns against entrenched Tea Party conservatives if it chose to do so.

Still, the Tea Party is hardly facing an existential crisis. Though voters are overwhelmingly displeased with the shutdown and furious with Republicans, that anger can certainly dissipate before the next election.

Moreover, while the public as a whole doesn't like the shutdown, one group does: The Tea Party. In other words, the very people whose active engagement in primary campaigns put these lawmakers in power in the first place.

Plus, as Slate's Dave Weigel noted, the effort is, so far, limited to a handful of districts: "Four members in trouble does not equal much of a backlash in a 233-member conference."

For now, the Tea Party as a whole is facing nothing more than a rather mild threat from the center. If the shutdown drags on much longer though, or if the nation really does default on its financial obligations, calls for Tea Party heads from the business community could certainly grow louder.