“Our constituents don’t trust our government,” Cotton said. And he is reluctant to pass even pieces of immigration reform that he thinks are needed — like a better tracking system for people in the country on visas — because he is concerned they could become “a Trojan horse in a conference committee for a package that puts legalization first and enforcement later.”

Top Republican and Democratic leaders on Capitol Hill see the momentum swinging decidedly against getting a deal this Congress. Rubio persuaded only 13 fellow Republican senators to back the bill; the editors of the National Review and Weekly Standard offered a rare, joint editorial in opposition to it this week; and private GOP headcounts show only a small fraction of House Republicans would ever vote for anything approximating the Senate deal.

Rep. Steve King (R-Iowa), a leader of the House’s hell-no-on-immigration-reform caucus, held a jam-packed meeting Monday night to walk through why his party should proudly defeat the bipartisan bill. King said the Senate’s immigration plan would help “elites who want cheap labor, Democratic power brokers, and those who hire illegal labor.”

“It would hurt Republicans, and I don’t think you can make an argument otherwise,” King said. “Two out of every three of the new citizens would be Democrats.” Some might dismiss this as the rantings of a bombastic right-winger — but his take is mainstream theology among House Republicans.