From Gabriel Sherman writing for New York Magazine:

When it comes to dealing with rogue states, Fox News has a firm editorial philosophy: You don’t negotiate. Roger Ailes is learning that the same logic applies to a rogue candidate. Last night, Donald Trump took to Twitter and blew up the uneasy truce Ailes had brokered with him two weeks ago following Trump’s attacks on Fox star Megyn Kelly after the first GOP debate. “I liked The Kelly File much better without ‪@megynkelly. Perhaps she could take another eleven day unscheduled vacation!”Trump tweeted as Kelly began her broadcast. Moments later, Trump retweeted tasteless comments from his followers. “The bimbo is back in town,” one read. “She has come back looking like Nancy Grace,” said another.

This morning, Ailes returned fire with much more force than he mustered during the initial imbroglio, when he muted his defense of Kelly in order to make peace with Trump. “Donald Trump’s surprise and unprovoked attack on Megyn Kelly during her show last night is as unacceptable as it is disturbing,” the Fox chief said in a statement, which called on Trump to apologize to Kelly. “We have never been deterred by politicians or anyone else attacking us for doing our job, much less allowed ourselves to be bullied by anyone and we’re certainly not going to start now.” Fox’s foot soldiers also fired shots: Bret Baier, Bill Hemmer, and Dana Perino were among a number of the network’s hosts posting pro-Kelly tweets in what looked like a coordinated defense.

[…]

Trump’s feelings are just as personal. On August 12, two days after agreeing to the truce, Trump steamed in private while reading a report by CNN media correspondent Brian Stelter that Trump felt took a pro-Fox slant. “We resolve this now or go to war,” the piece quoted Ailes saying. Trump, according to a friend who spoke with him, felt Ailes was spinning in order to damage him. “I know exactly what they were doing,” Trump told the friend, who says it took a lot for Trump to keep his mouth shut that day. “When Ailes was putting out those stories saying he had won, I just kept quiet. Aren’t you proud of me?” Trump told the friend. (A Fox spokesperson didn’t respond to a request for comment.)

It’s now harder to see an end to the Trump-Fox war soon. As I reported this week, Trump’s poll numbers remain strong and he’s building a robust campaign operation, which is a threat to Ailes’s political project: “Roger says Trump is unelectable. His goal here is to save the country,” a source close to Ailes told me.