Conservative Republicans in the House are demanding LGBT language be removed from the United States-Mexico-Canada Agreement (USMCA).
The recently revamped NAFTA agreement includes a pledge to implement "policies that protect workers against employment discrimination on the basis of sex, including with regard to pregnancy, sexual harassment, sexual orientation, gender identity."
Such language, Politico reports, is unprecedented in a US trade pact.
The LGBT provisions were pushed by Canadian Prime Minister Justin Trudeau, whose administration holds gay rights as a major part of its agenda.
However, a group of 40 US congressmen penned a letter of protest to the Trump administration saying the trade agreement is no place for the adoption of social policy.
"It is especially inappropriate and insulting to our sovereignty to needlessly submit to social policies which the United States Congress has so far explicitly refused to accept," they wrote in the Nov. 16 missive.
One of the signatories, Rep. Doug Lamborn (R-CO), even went so far as to say that, for him, the provisions could be a "deal killer."
"This is language that is going to cause a lot of people to reconsider their support of the trade agreement, and to the point that it may endanger the passage of the trade agreement unless something is done," Lamborn told Politico.
"At this point I'm a 'no' vote and I would encourage others to be a 'no' vote unless something is done," he said. "And things could be done within the agreement."
It's unclear, however, whether Canada's prime minister would be willing to drop his LGBT demands.
"We got to a good agreement that I think represents Canadian values, Canadian approach, but also values that are broadly shared amongst citizens of our three countries," Trudeau told reporters Sunday.
Meanwhile, the lawmakers are urging President Donald Trump to remove the language from the agreement before signing it at the end of November.