Ben Shapiro writes at National Review Online about a troubling aspect of President Trump’s approach to public policy.

Trump doesn’t have a fully formed ideology. This was seen by his supporters as a plus: Because he wasn’t in thrall to any one notion of the world, their thinking went, he would approach each issue with an open mind, never bound by ideological rigor. He could be a freewheeling pragmatist.

Unfortunately, even those who lack an ideology have a worldview, and Trump’s is essentially self-centered: What is good for his popularity is good for the world. This, it should go without saying, leaves him subject to co-option by those with a more ideological bent. When reality hits him in the face, he reacts spontaneously — and in doing so, he aligns with movements that have long pre-existed him, and that cheer him along. Spurred by that applause, he is drawn into the orbit of those ideologues who supply it.

That’s precisely how Trump ended up in the camp of the nationalist-populists during the election cycle. He articulated a knee-jerk sentiment about illegal immigration, Steve Bannon and the Breitbart crowd cheered, and so he doubled down on that sentiment. (He admitted as much himself during the campaign, stating that he simply invoked the border wall every time crowds began to get bored.) It’s the likely reason for his the warmth he showed toward Vladimir Putin before the Syria strike once again soured U.S.–Kremlin relations: Putin had been quite warm toward him and his allies, and Trump enjoyed the approval.

This is the Trump pattern: react, wait for applause, and then cater to those clapping.