This is a good piece by Santiago Zabala on "populism," a word that gets tossed around a lot these days about US and European politics: Don't be afraid of populism Aljazeera 16/19/2016.
When the American TV pundits use it, their working definition doesn't seem to go much beyond "something vaguely disreputable." This column even cites the recently-deceased political theorist Ernesto Laclau's work on the topic.
If you ever hear Chuck Todd or someone else on the Sunday morning shows mention the name Ernesto Laclau, it's probably a sign that something really dire has happened. Like a major rift in spacetime or something along those lines.
I like the fact that Zabala makes meaningful and realistic distinctions. "If populism is now the only available political form able to deepen the central value of equality that governs modern democratic societies, we must remember that there is a substantial difference between right-wing and left-wing populism in Europe."
He doesn't get into the concept of "sucker populism," a term used to describe the superficial notion in American politics that "left" and "right" populists can form some kind of substantive political coalition of a strategic kind, as distinct from shared positions on some individuals issues. But the distinction Zabala makes between current North Atlantic versions of left and right populism is very relevant to the "sucker populism" analysis.
In memory of good old William Jennings Bryan, I'll note here the original movement that used the name "populist" for itself was very much a left-leaning reform movement of workers and farmers.