As they noshed on sushi and Thai-inspired taquitos on Sunday evening, klezmer music wailing in the background, the wealthy guests at the Zionist Organization of America’s annual blowout marveled at the right-wing celebrities in their midst. Sean Spicer and Sebastian Gorka couldn’t walk five feet without being asked for selfies. Alan Dershowitz held court over a small crowd of journalists. Senator Tom Cotton gamely mingled with Joe Lieberman, Chris Ruddy, and other members of the hawkish, pro-Israel power elite. But it was Steve Bannon, self-proclaimed “Christian Zionist” and the evening’s most notable speaker, who drew the most whispers (and, befittingly, a crowd of protesters outside Manhattan’s Grand Hyatt), rolling up just 10 minutes before the dinner began. Conspicuously absent from the roped-off V.I.P. table, however, was the Z.O.A.’s biggest donor, and perhaps the most powerful pro-Israel American of them all: Sheldon Adelson, whom Bannon was slated to introduce on stage. (Morton Klein, the president of the Z.O.A., told The Hive that Sheldon and his wife Miriam had been caught up at a Yad Vashem board meeting and were unable to attend, sending a statement to be read aloud at the end of the night.)

Though his absence went largely unremarked upon, a source told me that some in the crowd were surprised the next day when Adelson, the casino billionaire and wealthy Republican kingmaker, issued a public statement leaving no doubt where he stands when it comes to the Breitbart chairman’s quest to overhaul the establishment Republican Party, reshaping Congress in his image in 2018. “The Adelsons will not be supporting Steve Bannon’s efforts,” Andy Abboud, Adelson’s spokesman, told Politico on Monday, saying that instead they would back his establishment rival, Mitch McConnell, “100 percent. For anyone to infer anything otherwise is wrong.”

The statement reads as an awkward coda to Bannon’s remarks at the dinner, which praised the mogul for standing by Trump after the Access Hollywood tape leaked during the election. “Sheldon Adelson didn’t cut and run,” Bannon told the moneyed crowd. “Sheldon Adelson had Donald Trump’s back. Sheldon Adelson offered guidance and counsel and wisdom of how to get through it. He was there for Donald Trump about how to comport oneself and how to dig down deep, and it was his guidance and his wisdom that helped get us through it.”

It’s unclear to what extent the statement comes as a blow to Bannon, given that there’s some doubt Adelson supported the Breitbart News chief’s populist insurgency in the first place. Back in October, Politico reported that Adelson, who is more traditional when it comes to domestic policy, met with Bannon privately to discuss Israel-related issues, on which they share similar views, but declined to fund his congressional midterm efforts. The Bannon camp downplayed Adelson’s statement, saying that it was inevitable the two men would not see eye to eye, and that Bannon had not asked Adelson for money—“How do you lose someone you never tried or expected to get?” Andy Surabian, the director of the Bannon-backed Great America PAC, told me. But several people close to Adelson told Politico they had ”grown concerned” about his ties to Bannon, who is finding it difficult to shake off his veneer as an anti-immigrant, anti-trade firebrand with an unfortunate link to white supremacism.

Bannon’s steadfast support of Roy Moore, the Senate candidate he backed in Alabama’s G.O.P. primary against McConnell’s preferred candidate, Luther Strange, hasn’t exactly helped his cause. Over the past week, Moore has been slammed with multiple allegations that he molested teenage girls when he was in his 30s, seemingly validating McConnell’s charge that Bannon’s populist-nationalism would end with unelectable Republican candidates. (Bannon, naturally, blamed the media for pursuing an anti-Moore agenda, and made sure to issue a general denunciation of the press during his Z.O.A. remarks.)