The political and media world seemed shocked this week when Megyn Kelly sat down for a warm interview with Donald Trump. She tossed him velvety soft questions like, "When did you realize you could be president?", sought to discover whether anyone had ever "hurt [him] emotionally," and peppered him with hard-hitting queries on his favorite book and movie. Kelly can of course do any kind of interview she likes, but it's as good a marker as any that Fox News is now thoroughly behind Donald Trump's candidacy for the White House.

If you've watched the network up until now, you might not have been so sure. But when you understand the function Fox serves for the conservative movement and the Republican Party, you realize that they had to be tough on Trump — at least a little, and at least for a while.

That's because in a presidential primary, it's part of Fox's job to vet the Republican candidates — testing them, probing them, and seeing how they stand up to pressure. That's why it was more than appropriate to have Fox anchors moderating primary debates, where on occasion they were quite tough.

Fox has always been more partisan than ideological: Its hosts certainly advocate for conservative ideas, but its political lodestar is the interests of the Republican Party. And it's the great genius of Roger Ailes, the network's chief for the two decades since it was founded, that he has been able to simultaneously serve both the GOP's interests and the goal of making gobs of money.

Before the primaries are over, the party's interest lies in identifying the strongest possible candidate and weeding out the weak. Once the nominee is chosen, however, everything shifts. That's why you're unlikely to hear anything but the mildest criticism of Trump on Fox from now on. Despite his feuds with the network up until now, he's the party's guy, and they're stuck with him.

Much more so than any liberal outlet does for its side, Fox sets the tone for the entire conservative media, and even the entire conservative movement. If you're a conservative it's where you can go not only to get validation for your beliefs, but also to learn what your leaders want you to know: what issues are important; the key reasons Democrats are wrong about everything; and perhaps most critically, what you're supposed to be angry about.

Because anger is the fuel that drives conservative media forward and keeps viewers coming back. It's what has made Fox so successful; if Sean Hannity and Bill O'Reilly couldn't be angry, they would almost cease to exist. And by the way, don't think Megyn Kelly, despite her occasional expression of a less-than-fully-conservative view, isn't a part of that system. There may be no one in the media who spent more time trying to get people riled up about the case of a few New Black Panther Party knuckleheads who stood around outside a Philadelphia polling place in 2008, allegedly intimidating voters; to hear Kelly tell it, there was a conspiracy between Barack Obama and Eric Holder to cover up this dire threat to white people's rights everywhere.

Now that the primaries are coming to an end, the full measure of Fox's fury will be directed at Hillary Clinton, and their viewers will be assured that should this criminal lying castrating harpy be allowed into the White House, the ruin of America will be all but complete. The message will be relentless, repeated, growing in urgency as November approaches. And it's no easy job; as Judd Legum documented, when The New York Times published an article on Trump's boorish behavior toward women, Fox personalities offered 15 separate excuses for him in the course of a single day.

But it's not like they're entering unusual territory. After all, Trump's greatest appeal is to your typical Fox viewer. The median age of the network's audience is 68, and some shows skew even older. After watching Bill O'Reilly rant every night about how immigrants are destroying our culture, black people need to pull up their pants and stop committing crimes, political correctness is killing us, the white man is oppressed, and America was a heck of a lot better when he was a kid, who else would they have voted for? As media reporter Gabriel Sherman writes, "According to one Fox News producer, the channel's ratings dip whenever an anti-Trump segment airs. A Fox anchor told me that the message from Roger Ailes' executives is they need to go easy on Trump."

And one of the most important things Fox will tell its viewers is that the liberal media are hopelessly biased against the Republican standard-bearer. It's long been an effective message: Listen to us, because you can't trust anyone else. But that's part of the reason why Fox is a mixed blessing for Republicans.

The benefits to the GOP from Fox are fairly obvious. The network gives them a forum for their views and their personnel, and can help push their ideas into more mainstream media through the sheer power of repetition. It enables the party's messages to be quickly disseminated to its rank-and-file, communicating to Republicans everywhere what's important, what they should think, and what they should be agitated about.

But it also helps foster a dangerous insularity, in part because of how good it is at convincing conservatives that if they see anything in the media that challenges their perspective, then it can only be a pack of lies. We saw that in 2012, when everyone in the party, up to and including Mitt Romney himself, discounted what the polls said and were convinced that Romney would walk to an easy victory. After all, how could a majority of voters possibly support a president as villainous as Barack Obama, when they had made his misdeeds so clear? When the results came in, the overconfident candidate and his campaign were utterly baffled by what had occurred.

Don't be surprised if they haven't learned their lesson and something similar occurs this year. Just like Trump himself, who's always able to find the one poll that says he's marching to victory when there are 20 that say he isn't, Fox will present to Republicans a picture of the world as they'd like it to be, where America is coming to its senses after eight long years of misery and a noble champion has risen to deliver us from our despair.

It may not be true, but it'll be great for ratings.