[kristopolous]

Spain had a monarchy And a populist dictator, Franco. Japan had an emperor during WW2 and the Nazis caucused with the Monarchist party DNVP when they were forming a coalition government. Some of the Monarchists even went on to occupy Hitler's cabinet. King Victor Emmanuel III also ruled Italy during the reign of Mussolini.

So I'll have to toss a citation needed on this one. I think history demonstrates a pretty strong overlap between those who support monarchs and populist dictators because in practice, they are structurally pretty similar.