Amorality causes failure
It is known that populists have always been immoral. Like the putschists who invest power by arms, the populists do so with a discourse that exploits the anger of those left behind by the elite in power and have nothing to lose.
It is also known that once in charge, the populists distribute the privileges to the fringes which will keep them in power and not to their voters. The anger of the latter was only a launching pad.
Ideas subject to natural selection
ideas are subject to the laws of natural selection, the more moral the idea, the more it has the chance to last. Indeed, populism succeeds punctually on pointing the immorality of the situation.
The theoric foundations
To schematize and categorize, two theories are antagonistic in this topic. On the one hand, the liberal current, which believes in interdependence, is more optimistic, and trusts in the perfectibility of humans.
Professor Joe Nye : Do Morals Matter? The American Election and Donald Trump (Exeter College).
And on the other hand, the realistic current, who rejects the so called idealism, and justifies populisms.
Professor Randall Schweller tells us about Realism and the role of power in international relations (Soomo).
The lesson is in the endings.
In my humble opinion, history has always proved the former to be right.