For weeks they’d been negotiating with Freedom Caucus Chairman Mark Meadows in a quest to clinch an immigration deal that could pass the House. But whenever the two sides got close, they said, immigration hard-liners would ask for more. Then, on the morning of a scheduled June 21 vote, moderates got their hands on an explosive missive from the Freedom Caucus’ top staffer: an email warning group members that voters would punish them for backing any bill with a whiff of “amnesty.”

“This is bull—-,” Rep. Tom MacArthur scolded Meadows at a meeting in Speaker Paul Ryan’s office that day. The New Jersey Republican, who had worked closely with Meadows in the past and wanted a deal, demanded to know why Meadows appeared to be backing away from a bill he helped craft.

Rep. Jeff Denham (R-Calif.), a leader of the pro-immigration reform centrists, read the Freedom Caucus email aloud, as Meadows insisted he had no knowledge of it. Rep. John Katko (R-N.Y.) said he’d been warned not to trust the Freedom Caucus, seething that he’d never make that mistake again.