Populist movements in Western democracies generally don't last long. Instead they usually morph quickly into their own version of the establishment. I think that the reason for the short lived populist aspect of a political movement is reasonably simple. Populist movements are expressions of anger, discontent, and fear rather than expressions of principle. When there is a welling up of fear and discontent, the conmen and shysters come out of the woodwork to take advantage of it because conmen look for easy marks, and when it comes to politics in particular, angry fearful people are easy prey. When these emotions take hold of people, they don't think straight. Instead, they look for people who sooth them, who provide easy answers to complex problems and make them feel like everything is going to be ok. Thus the followers of populist conmen are fervent in their belief and passionate in their commitment to their saviour. As a result of this combination of fervency and fear and anger motivated passion, populist leaders can basically do anything they want and their support will stay relatively steady for some time, as long as they keep spouting their simple, soothing message. In this regard, Trump's now infamous observation that it wouldn't hurt his popularity if went out on 5th Ave. and shot someone, is ominously revealing. The most diehard followers of a populist leader have zero interest in facts, and shockingly little interest in the actions of their leaders. This is because such followers are being feed the political equivalent of soma which puts them in a sort of trance, And as long as their leader proclaims the right trigger phrases, espousing simple ideas about how everything is going to be fixed and all the "bad stuff" and "bad hombres" will expunged, nothing else really matters.
Ironically, this is where populist movements tend to come unstuck. When a populist leader gets swept up in the adulation, even if their intentions were initially good (which they seldom are), they realize that they don't have to do any of the things that their followers want, or they only have to make minimal, often cosmetic efforts to maintain the drug-like trance in which they have put their followers. The problem is, of course, since most populist leaders are primarily interested in enriching themselves and their social/ideological allies at the highest level, they quickly become the establishment that they swept to power to oppose. Thus things don't really change, at least not for the better, and often for the worse. And when this happens, the soma trance wears off just enough people for the populist movement to lose its momentum and things become unstuck. One of the problems, of course, is that populist movements often leave in their wake a rightwing political establishment that can last for years.
This is precisely the scenario that played out in Canada. The populist movement known as the "Reform Party" swept into Ottawa with all sorts of populist promises, feeding off socially conservative ideas and white-privilege fears. The "Reformers" said that they wouldn't take the rich Parliamentary pensions, that they would allow all sorts of free votes in the House of Commons, they insisted that their leader would live in the luxurious housing due an opposition leader or a Prime Minster, and that they would enact legislation based upon its social popularity not based upon some niche interest group. All those commitments lasted about five minutes once the Reform leaders found themselves in the luxurious and complex world of actual legislative politics. But as the Reform movement burned, from the ashes was born an establishment party that enhanced and magnified the very things that people who supported the movement had rebelled against in the first place. So we were left with a party that was less interested in transparency than any government in history, ruled for a very small percentage of the population, was comically dishonest, lined their pockets and the pockets of friends like never before, and was more intrusively sinister than ever in people's personal lives.
The reason that a political movement that started out of anger and claimed to be interested in more responsive and open government could quickly turn into its opposite is because of what we have come to know as "cry-baby conservatism."
Playing the victim is a integral part of modern day conservative parties and movements. Leaders like Harper and Trump continually harp on this idea that the establishment and the media is all against them and that they have to be mean and secretive and dictatorial because otherwise their opponents will win. And the cry-baby conservatives use this simple political strategy to consolidate their power and create a political machine that is often actively acting in ways that are contrary to their stated beliefs and those of their followers. Thus conservative followers in Canada barely noticed the irony when Conservative government cabinet members railed against the elites while at the same time riding in limousines to work. Similarly in the US we have a billionaire president with billionaire cabinet members who cry out against the establishment and have already instituted laws that will make them richer and the average person significantly poorer.
What is clear is that as the Trump movement progresses, the idea of "draining the swamp" and changing the political establishment will feature less and less in the Trumpian narrative. More and more of the Trump followers will accept the idea that the Trump government has to create their own establishment, their own "swamp" if you will, in order to overcome all those "liberal" and media forces that are arrayed against them. Thus people will accept much greater corruption and criminality, than they witnessed in those they initially sought to replace. As I said at the beginning, this is because the followers of leaders like Trump, are not motivated by a principled stance for better, more responsible, democratic, and transparent government. Rather, they are whipped up by anger and fear of a changing world.
Of course, as the populist aspect of the Trump phenomenon wanes, many will come out of the political trance and realize that they have been had and this may result in a significant shift in a different political direction. Either way, the populist movement will be dead. The only question is, will it leave in its wake a political establishment that is able to hold on to power for a while or will it, with its criminality and corruption, undermine the delusional state that brought it to power in the first place, thus causing a kind of counter rebellion?