A bipartisan working group in the Senate has signaled it’s reached a deal on border security after months of negotiations, but a raging dispute within the Republican Party has thrown that effort into doubt as Senate Republicans weigh the political wisdom of that compromise.

Senate conservatives have for weeks expressed opposition to the border talks as Sens. James Lankford (R-OK), Kyrsten Sinema (I-AZ), and Chris Murphy (D-CT) hammered out an agreement with the White House that would tighten asylum standards and give the president a new expulsion authority.