The business community, fully against the National Labor Relations Board's "joint employer" doctrine, is leaving nothing to chance when it comes to undoing the rule. Groups are now working on four simultaneous fronts to loosen or destroy the rule: Through the legislative process, the congressional appropriations process, lobbying the Trump administration, and bringing cases before the board itself.

That's a testament to how deeply the doctrine, a potentially vast expansion of legal liability for corporations, worries its critics despite it being only about two years old and thus far having had scant effect on businesses. Trade associations are nevertheless terrified of its implications and have worked overtime to get Democrats on board with the effort.

Joint employer refers to when one business can be held legally liable for workplace violations at another business. Traditionally, the standard applied when one business had "direct control" of another business' workplace policies, such as a subsidiary.

"Virtually every Democrat I have talked to has a lot businesses in their district worried about this," said Rep. Bradley Byrne, R-Ala., one of the lawmakers leading the effort.

That makes it one of the rare congressional efforts that might have enough bipartisan support to be passed this fall, though that puts some Democrats in a tight spot since organized labor backs the expanded definition. "Some people are saying that they cannot cosponsor, but they'll be with us on the floor vote," said a source at one major trade association.

It became worse for businesses 2015, when the NLRB, which is the nation's top labor law enforcement agency, changed the joint employer standard to the much vaguer "indirect control," which could cover every company that franchises its brand. The NLRB has used the rule to pursue a major labor rights case against McDonald's Corp., among others.

The change was part of a much broader push by President Barack Obama's nominees to the board to reinterpret old rules and give them a pro-labor twist. The broadened standard was adopted by other federal agencies as well, including the Labor Department.

It has also prompted a major push from business to revert matters to the standard before 2015. For many major trade associations, this is their No. 1 priority.

The Trump administration is sympathetic. Labor Secretary Alexander Acosta announced in June the department would no longer pursue cases based on the NLRB's doctrine.

The White House is trying get the NLRB to reverse itself as well, but that is not as easily done. The board is an independent agency whose five members serve staggered terms. At the moment, the board has four members: two Republicans and two Democrats. Trump has moved to give it a GOP majority for the first time since President George W. Bush. The Senate has yet to confirm President Trump's nominee for the last open seat, attorney William Emanuel. The Senate is expected to take up the nomination in the coming weeks.

Even then, reversing the 2015 Browning-Ferris rule will require a new case to come before the board, a process that could take several months. In addition, the term of Republican Chairman Philip Miscimarra runs out in December, meaning the Senate will then have to approve another nominee to give a GOP majority.

On the legislative front, House Republicans added a rider to the appropriations bill covering the Labor Department and related agencies prohibiting the NLRB from enforcing the joint employer doctrine. "It will likely be part of a final negotiation [with the Senate] later this year," said a committee source who requested anonymity.

Most business groups want something that goes even further than tying the board's hands, however. They want legislation covering all workplace law, including civil litigation. Byrne's Save Local Business Act would rewrite the National Labor Relations Act to state that joint employer only applies when a business "directly, actually, and immediately" controls another businesses' workplace policies. It would extend this declaration to the Fair Labor Standards Act as well.

The legislation, which is set to be marked up by the House Education and Workforce Committee this month, has 43 cosponsors, including two Democrats. The business lobby thinks it can muscle this through the Senate as well.

Business lobbyists argue the Democratic support is much broader. Getting a strong bipartisan vote in the House is necessary to get it moving through the Senate. Without it, the effort could falter.

Randy Johnson, the Chamber of Commerce's senior vice president for labor and immigration policy, predicted at a Labor Day press briefing they would have enough Democratic support to get it through the Senate as well.

"Among a lot of labor issues, I think we have got a shot at this in the Senate. Now, we might take some compromising at the end but there is a lot of angst over the Browning-Ferris decision ... There is a lot of push behind this.

"Now, it could be that a case will move through the National Labor Relations Board that reverses Browning-Ferris and that would take the wind out of the sails of the legislation. We'd be happy with that too," Johnson said.