In the summer and fall of 2016, America was under clown attack. First in South Carolina, then across the country, residents reported sightings of menacing clowns, in the woods, on the streets and on social media.

It was as if life were offering a unsubtle metaphor for a unsubtle political season. The clown — the funny-haired figure from the entertainment world— had become angry and powerful, conjuring malicious minions from the shadows.

This is the comic-macabre idea that “American Horror Story: Cult,” beginning Tuesday on FX, grabs hold of, shakes up and sprays like bloody seltzer all over its audience. As a first draft of political-cultural history, it’s a cartoonish mess. But in its feverish way, it captures the feeling of living inside a joke that’s gone out of control.

As it begins, Ally (Sarah Paulson) is watching the election returns on MSNBC. When the presidency is called for Donald J. Trump, she howls as if she’s seen a monster. “Merrick Garland,” she wails. “What’s going to happen with Merrick Garland?”