If you haven’t heard, Donald Trump and his MAGA Republicans are planning a coup. “A Trump dictatorship is increasingly inevitable,” Robert Kagan, an editor at large at the Washington Post, writes in a recent 6,000-word essay that compares America’s fractious democracy with Weimar Germany.

Budding opinion writers are instructed not to draw inapt comparisons to Hitler, yet Mr. Trump’s opponents are casting aside such conventions in much the same way they’re jettisoning political and legal ones. Only by convincing themselves that Mr. Trump threatens the existence of the republic can they justify their own weaponization of government to stop him. “When a marauder is crashing through your house, you throw everything you can at him—pots, pans, candlesticks—in the hope of slowing him down and tripping him up,” Mr. Kagan writes.