“There are some in our caucus that, regardless of what the bill says, are not going to support it. And that’s life.”

Sessions’s energetic pushback to a growing tide of bipartisan support for a bill he despises has immigration opponents singing his praises.

“From the day this was introduced, he has been exposing every flaw, every weakness, every attempt to pull the wool over his eyes,” said Ira Mehlman, a spokesman for Federation for American Immigration Reform. “He has sort of been the Paul Revere of this bill.”

Sessions’s stamina cannot be overstated.. The 66-year-old — a former Alabama attorney general — was on the Senate floor until 10:30 p.m. on Thursday and has spent hours on his feet in the past week, reading speeches and often ad-libbing the reasons he hates every bill provision.

“He is quite the scrapper,” observed Beck.

Beck said when he met Sessions in the 1990s and they talked immigration, Sessions “started finishing my sentences.”

Even Sessions’s political foes admire his commitment to the cause. “I wish I could bottle Senator Sessions’ raw anger and sell it to college students as an energy drink. I’d make millions,” said a Democratic aide.