As I left the United States Pavilion at the Venice Biennale, I felt like I’d just finished a puzzle that mocked me for solving it. Every two years, countries from around the world select an artist (or a group of artists) to showcase at contemporary art’s most prestigious festival. This year, after a process laden with complication and controversy typical of the second Trump administration’s cultural efforts, the United States picked the 55-year-old sculptor Alma Allen. He filled a series of