The Mule had recently finished writing “Funny Little Tragedy,” a hard-charging, punk-inflected rocker; a song, the guitarist felt, was different from anything the band had ever done.

Far from the MAGA fantasy you might have feared, Clint Eastwood's “The Mule” is a poignant, funny, and thrilling work of self-commentary. At 88 years old, Clint Eastwood might be the hardest ...