In 2018, the United States stands with dukes up against much of the world. And a scan of the upcoming art season suggests that museums are tightening borders too. Where are the big shows of art from the Global South: Africa, Asia, South America? The United States and Europe dominate the turf.

Do we really need another Andy Warhol retrospective? The Whitney Museum of American Art thinks we do, and maybe they’re not wrong, given the times. Warhol, celebrity-addled but acid-eyed, has been an apt fit for every truly nutzoid American moment. In “Andy Warhol — From A to B and Back Again,” he surely will be again (opening Nov. 12).

“Bruce Nauman: Disappearing Acts” at the Museum of Modern Art and MoMA PS1 (Oct. 21) is the 76-year-old artist’s second MoMA retrospective. (The first was some two decades ago.) But, again, the moment is ripe for an artist with a radar for the civic surreal. His famed 1987 (Reagan-era) video “Clown Torture” is one of the funniest works of political revenge-porn ever made.