"What appears to be happening is that some of those who claim to be champions of conservatism are actually champions of populism. They are not the same thing, philosophically or temperamentally. (Populism has been defined as “an ideology which pits a virtuous and homogeneous people against a set of elites and dangerous ‘others’ who are together depicted as depriving (or attempting to deprive) the sovereign people of their rights, values, prosperity, identity and voice.” It has different manifestations, some more responsible and some less, but resentment is often a key ingredient in populism. It’s also a movement that’s been historically susceptible to demagogues, a concern held by philosophers from Plato and Aristotle to the American founders.)
There is room for populism within conservatism — it can be a “cathartic response to serious problems,” in the words of George Will — but it should not define conservatism. Yet increasing, in some quarters, it is; and the sympathy and support some on the right are giving to Donald Trump is clear evidence of this.
This distinction between conservatism and populism goes a long way toward explaining why different people on the right, who might otherwise agree on a fair number of things, react in fundamentally different ways to Donald Trump. And it’s why the Trump candidacy may well catalyze a broader, clarifying debate about what the true definition of conservatism is. For many of us who are conservative, Donald Trump not only doesn’t define it; he’s antithetical to it."
Wehner, Peter. "When Populism Masquerades As Conservatism." Commentary Magazine, 23 July 2015.