The same thing that is powering most other political figures, all of which can be termed “Populists”

People are angry about a number of things. The wealth gap is very large, they are constantly told that the reason they aren’t doing well in life is because of their own failings, whilst they watch elites with political access get away with things they can only dream of. They’re being told immigrants and/or AI’s are coming for their jobs. They’re being told they can’t have what their parents or the wealthy had because Climate Change, or because inflation.

This generates a great deal of friction, which in turn pushes people to radicalize their beliefs. You can’t continue to sell a liberal, centrist viewpoint of the world when it simply isn’t working for them. They might cotton on to “dumb” ideas, but this does not mean that they are stupid. It means that they are angry. This is is demonstrative of a deeper problem that is being very deliberately ignored or papered over, because those in power have a vested interest in keeping the gravy train running for as long as possible. The sheer scale of the problems we now have to deal with are exceeding the kinds of moves and actions most Western politicians have learned over the years, so we aren’t getting appropriate results out of our political apparatus.

In times such as these, many people will look to the past for ideas on how to deal with their current situation. They sometimes come back with bad ones, sometimes they come back with good ones, and the pre-existing power structure will do everything it can to resist both of them, because to change is tantamount to completely losing grip on power for many of the people invested in the way things are. They cannot adapt, and once gone they will never get it back.

So we have a kind of a worst-case situation with a maladaptive leadership, extreme public resentment and actual natural/physical catastrophes forming a kind of crucible that this civilization needs to endure.

The trumps/erdogans/farages/orbans/lukashenkos/putins/meleis of this world are symptoms of these issues.