Before President Donald Trump can get his new North American trade deal passed, he’s got to overcome stiff congressional opposition — from his own party.

Senate Republicans say that unless the president removes steel and aluminum tariffs on U.S. allies, his NAFTA replacement isn’t going anywhere. And that’s assuming the president doesn’t follow through with his threat to impose new levies on foreign auto companies, many of which have factories in Southern GOP senators’ backyards.

“I don’t think there are going to be 51 votes to pass it with the tariffs still outstanding. So as a practical matter, that’s a reality we’re all going to have to deal with,” said Sen. John Cornyn (R-Texas). “I also think the Mexico government and the Canadian government are unlikely to approve the deal with the tariffs still standing.”