I had heard secondhand accounts of disturbing right-wing tendencies of his. I had read Auden's poem saying Yeats would be forgiven because he wrote well. But it wasn't really clear to me what he would be forgiven for, until I read the selections from On the Boiler, originally published sometime in 1939 after Yeats had died in January of that year, which are collected in the volume Explorations, in which he very strongly favours eugenics, and has some positive things to say about "the Fascist countries," and declares that "the new-formed democratic parliaments of India will doubtless destroy, if they can, the caste system that has saved Indian intellect" (p 424), and poo-poos all suggestions that poor children would thrive given the advantages of the rich or that rich children would struggle facing the challenges of poverty. He deplores Socialist "slaughter" and appears not to have heard of Guernica or other right-wing slaughters. Having died just before the beginning of World War II, we cannot know how or if he would have responded to the horrors of the Holocaust or the slaughters perpetrated by Fascist Japan. But he does fantasize a bit about war to come, waged in favor of the upper classes and calls it a good thing, a healthy shock which will promote learning. World War II was indeed shocking, but not good. On the Boiler is shocking, but not in a good way.
On p 429 Yeats writes that
"I am philosophical, not scientific, which means that observed facts do not mean much until I can make them part of my experience."
Which sounds very nice at first, until one starts to wonder whether it was no more than a high-toned excuse to ignore whatever facts clashed with Yeats' cherished dreams. He was one of those Christians who dreamed of a chivalrous aristocracy which had little to do with the actual Medieval Europe and less with 20th-century fascism. The Nazi leadership was neither an aristocracy nor a meritocracy, and even if it had been aristocratic, one had to be quite blind indeed to miss all of the ill effects of inbreeding in the European ancien regime, worse than anything to be found in the most remaote and backwards peasant village. The one criticism of fascism which Yeats offers in On the Boiler is that the fascists states rewarded fertility among all classes. Yeats' eugenics favored bigger families in the aristocracy and few or no children for peasants or proles. With remarkable blindness, Yeats guesses (p 424) that this fascist encouragement of big families in all classes occurred only because of some unspecified pressure from democratic states. The reality, as plain to see as anything could be, was that the Nazis and the Italian fascists, even with their own unrealistic idealizations of aristocracy, valued an ethnic German or Italian peasant much more highly than a Jewish or Russian prince, and quite possibly higher than an Irish prince as well, or even a Japanese prince.