Channel 14, a brash right-wing Israeli television station, has long reflected the messaging of Prime Minister Benjamin Netanyahu, popularly known as Bibi, and appeals to his unwavering base of loyalists, the “Bibistim.”

Until recently, the station has also been ardent in its support for President Trump, especially after the two leaders joined forces to go to war against Iran.

That has all changed.

Since the American president announced the emerging cease-fire deal on Sunday, influential Channel 14 personalities have been lining up to vilify Mr. Trump and his top aides. Even before the details of the deal have been made public, it has caused widespread consternation in Israel because of its apparent shortcomings in addressing Israel’s security needs.

Mr. Netanyahu’s hawkish government has been careful not to criticize Mr. Trump openly, apparently for fear of provoking him. But his cheerleaders from Channel 14 might be saying the unsayable on behalf of the prime minister.

Adding to the sense of insult among Mr. Netanyahu’s proponents, Mr. Trump has been increasingly brusque in his dealings with the Israeli leader. Mr. Trump has publicly belittled Mr. Netanyahu, saying “he’ll do whatever I want him to do,” and confirmed that he had called Mr. Netanyahu “crazy” in a recent, expletive-laden phone call.

One of the first Channel 14 stars to assail Mr. Trump was Yinon Magal, the host of “The Patriots,” a combative talk show that airs every weeknight. “Trump came out a loser,” he wrote in a blistering social media post early Monday.

Mr. Magal, an abrasive character, had previously made no secret of his enthusiasm for Mr. Trump. On the night of the U.S. presidential election, he sported a “Trump 2024” baseball cap on air and joked with his studio audience that he would not reveal which candidate he was rooting for: “Donald or Trump.”

Now Mr. Magal and his colleagues have gone on the warpath. He described Vice President JD Vance, in Hebrew, as “scum” or a “lowlife.” He also accused Mr. Trump’s negotiators, Steve Witkoff and Jared Kushner, who is the president’s son-in-law, of selling out “their brothers in Israel.”

He went on to deride the pair as “Jewboys,” drawing condemnation from the Anti-Defamation League in Israel, which said that such an antisemitic slur had “no place in public discourse in Israel or anywhere else.”

Asked about Mr. Magal’s use of the term, Omer Meiri, a spokesman for Channel 14, said his comments “were made on his personal X account, not on Channel 14.”

When Mr. Magal was asked for comment about the matter, he responded by text message with a verse from the biblical Book of Esther, a book describing the Jews’ deliverance from annihilation in ancient Persia. The verse starts: “For if you remain silent at this time, relief and deliverance will arise for the Jews from another place, but you and your father’s house will perish.”

Mr. Magal said that he was generally expressing his own opinion and that he had not spoken with Mr. Netanyahu about the preliminary deal. But, he added, he imagined that Mr. Netanyahu was not happy with it, nor with “the crude and insulting way that Trump has suddenly started talking about the prime minister of Israel.”

Another Channel 14 star, Yaakov Bardugo, a political commentator who is close to Mr. Netanyahu and often viewed as articulating his positions, described Mr. Trump and Mr. Vance on air as “modern Chamberlains,” referring to Neville Chamberlain, the British prime minister known for his policy of appeasement toward Adolf Hitler.

Mr. Bardugo said Mr. Witkoff and Mr. Kushner were “a team of realtors” guilty of “total diplomatic bankruptcy.”

And on Wednesday, Shimon Riklin, another of the channel’s stars, wrote, in English, that Mr. Trump represents “total surrender to the ayatollahs in Iran.”

Mr. Meiri, the Channel 14 spokesman, denied any suggestion that the broadcaster was doing Mr. Netanyahu’s bidding. “Unlike Israel’s old media establishment, we believe in free speech,” he wrote in a text message.

“We do not take orders from politicians, nor do we give orders to our journalists,” he wrote, adding: “Since the new Iran deal was unveiled, Prime Minister Netanyahu himself has been criticized by the channel’s own reporters and anchors.”

Channel 14 began as a small, niche outlet focused on Jewish tradition. In recent years, it has become highly influential in public discourse, with prime-time ratings that have, on occasion, outstripped those of Israel’s public broadcaster, Kan, as well as more mainstream commercial channels.

Israeli media critics have speculated that the attacks on Mr. Trump may be intended to deflect any blame from the prime minister for a diplomatic debacle, given the broad discontent in Israel over the deal.

“We’re behind you,” Mr. Magal assured Mr. Netanyahu in his post.

In a televised news conference on Monday, Mr. Netanyahu was restrained when asked about Mr. Trump, saying that while he and the president “often see eye to eye,” they sometimes saw “less eye to eye,” as happened in “the best of families.”

Channel 14 has pulled no punches, however, amplifying the on-air barbs against Mr. Trump and his aides by posting video clips and transcripts of them on the channel’s website.

One such clip posted on Tuesday showed Yotam Zimri, a panelist on “The Patriots,” saying, “Trump is the president who gave us the most but also the president who disappointed the most.”

In another clip from a monologue, Yaara Zered, a Channel 14 political commentator, said, “The people of Israel were here before Trump and will be here after Trump.”