Donald Trump loves to criticize the “failing” New York Times, “dishonest” Politico and the “Obama network,” NBC. His attacks on the media resonate with his supporters, and he probably figures he stands to lose little if his nastygrams lead to negative coverage. Most conservatives don’t trust the Times, Politico and NBC — or the rest of the mainstream press — anyway, according to the Pew Research Center.

But conservatives do trust talk radio stars like Rush Limbaugh, Glenn Beck and Sean Hannity. Getting on their bad side could be more problematic, and right now Trump appears to be falling out of favor with one of the few segments of the media that carries real weight within his party's base.

He has already lost Beck, who last week told Fox News host Megyn Kelly (one of Trump’s favorite targets) that he’s not even sure the Republican front-runner would make a better president than Democrat Hillary Clinton.

“I know I won’t go to the polls,” said Beck, who said after Trump entered the race in June that he likes Trump personally but doubts his conservative credentials. “I won’t vote for Hillary Clinton, and I won’t vote for Donald Trump. I just won’t. … I know there’s a lot of people in the GOP who are like, ‘Look, he’s better than Hillary Clinton.’ Maybe. I don’t know.”

Meanwhile, Limbaugh, who has been sympathetic toward Trump, was clearly perturbed last week after the real estate mogul turned his rhetorical fire on conservative darling Ted Cruz, the Texas senator who looks increasingly like Trump's biggest competitor. Trump said last Sunday that Cruz has acted like “a little bit of a maniac” in the Senate.

“A genuine conservative, even in the Republican field, would not go after Cruz this way,” Limbaugh told his listeners. “So that just raised a red flag for me, made me somewhat curious.”

Limbaugh has previously said that Trump is “doing a great service” by “showing you do not have to fear being politically correct or violating political correctness.”

Few things could be worse for Trump — who has a history of being friendly toward Democrats — than to have Republican voters question his conservative bona fides.

Hannity, who has praised Trump's tax plan and defended him against critics of his proposal to close U.S. borders to Muslims, also took Cruz’s side after the “maniac” remark, saying on his radio program that Trump won’t succeed by ripping the Texan the way he has other opponents.

“I think there’s gonna be a difference in attacking Ted Cruz,” Hannity said. “Because Ted Cruz, when he did the filibuster in the Senate, that was loved by conservatives. They were cheering Ted Cruz standing up against what he calls the Washington cartel. So I’m not so sure that same strategy is going to be efficient as he’s going up against a strong conservative in the field.”

In the fifth Republican presidential debate, on Tuesday, Trump tried to smooth things over with Cruz, saying he “has a wonderful temperament” and is “just fine.”

That might be enough for now, but as Limbaugh said, the red flag has been raised. And while Trump seems happy to slash and burn his way through much of the press, he can’t afford to do the same with influential conservative talkers.

His supporters might not take marching orders from talk radio -- the truth of who makes up his base is more nuanced than some realize -- but in Trump's anti-establishment rhetoric they have heard echoes of some of their favorite media personalities. In many ways, Trump's campaign has resembled a traveling conservative talk show. Like a good host, he gives voice to their frustrations; it's one of the reasons why he has been embraced so quickly as a card-carrying conservative, despite what the National Review has referred to as his "progressive past."

If the real hosts turn on him — a move that gets easier and easier to make as Cruz strengthens in Iowa and looks like a real top contender — Trump risks losing that card and triggering the exodus that many pundits have always believed is inevitable.

Mocking and bullying members of the media has been a winning strategy for Trump so far. But there are certain members who could hurt him if they desert him.