The decision by House Armed Services Committee Chairman Howard “Buck” McKeon (R-Calif.) further lowers the odds that any immigration reform proposal will pass in the Republican-controlled House this year.

The move could also cause political trouble for a half dozen House Republicans who represent districts with growing immigrant communities. They are expected to face well-funded campaigns by Democrats and immigration rights groups to unseat them in the fall.

Two of them, Reps. Mike Coffman (R-Colo.) and Jeff Denham (R-Calif.), have been touting proposals that would allow qualified undocumented immigrants to enlist in the U.S. military and then seek to become legal permanent residents if they met certain service requirements. Other Republicans, mostly from western states, have been pressuring GOP leaders to allow votes on the proposals or include them in the National Defense Authorization Act, a comprehensive bill that is considered must-pass legislation.