The exclusion of a measure to extend compensation for people exposed to radiation from U.S. nuclear testing from the annual defense bill this week marked yet another fracture in the Republican conference.

The bipartisan amendment to the National Defense Authorization Act (NDAA) passed the Senate with a supermajority in August but was not included in the House version of the bill and was ultimately dropped from the final legislation. Co-sponsor Sen. Josh Hawley (R-Mo.) called its removal a “betrayal” of the country’s commitment to the victims of such radiation.