Mexico has sworn in its first woman president. This looks like a bold step for equality and progress—all the more impressive because the new president, Claudia Sheinbaum Pardo, is of Jewish origin. Her father’s parents immigrated to Mexico from Lithuania in the 1920s; her mother’s parents escaped to Mexico from Axis-aligned Bulgaria in the early 1940s. But Mexico is not advancing toward an egalitarian future. It is regressing into an authoritarian past. President Sheinbaum’s predecessor, Andrés Manuel López Obrador, systematically smashed the checks and balances of Mexican democracy, subjecting once-independent government institutions to the personal power of the president. Independence of the judiciary? Gone, abolished by the last major legislation of his presidency. Judges will now be elected by partisan ballots. Independent election administration? Crippled. Nonpartisan enforcement of government-transparency rules, nonpartisan antitrust enforcement, nonpartisan telecommunications regulation, nonpartisan energy regulation? Abolished, abolished, abolished, and abolished. Only the central bank, after a long struggle, will retain its autonomy from direct presidential control. The biggest question for the future of Mexico: Who will wield the power that López …