There was a certain point after 9/11 where he went from “libertarian with some bones to pick with Reagan and Bush” to “frothing at the mouth western chauvinist”. IIRC 300 was written before he went fully over the edge. The Miller who wrote Batman calling guns “the weapon of the enemy” and fighting a Superman who’d become an unthinking pawn of the government is barely the same Miller who wrote Batman as a cop-killing psychopath who kidnaps and tortures a 12-year-old Dick Grayson.