If President Donald Trump defies the courts by refusing to comply with their rulings, what will stop him? This question has suddenly become central to U.S. democracy, as federal judges have temporarily barred numerous administration actions, including ending birthright citizenship and granting Elon Musk’s team access to a Treasury Department payment system. Troublingly, Vice President J. D. Vance has repeatedly suggested that the executive should disobey the courts in certain cases, writing last weekend that “judges aren’t allowed to control the executive’s legitimate power.”

Conventional wisdom, dating back to Alexander Hamilton, is that independent courts should protect democracy; the judiciary, Hamilton argued, is an “excellent barrier to the encroachments and oppressions” of elected politicians. Yet Hamilton also observed that “from the natural feebleness of the judiciary, it is in continual jeopardy of being overpowered, awed, or influenced by its coordinate branches,” meaning the executive and Congress. Hamilton’s paradox is that courts are designed to restrain a powerful executive but lack a clear basis for their own power. When and how, then, do courts prevail over an executive who threatens to flout their rulings?

As a political scientist, I have researched this question by interviewing high-ranking judges and lawyers in backsliding democracies, collecting original data in Turkey, Israel, and Brazil. The answer: When courts confront a powerful, noncompliant executive, three paths enable the judiciary to stop an executive power grab. Each path musters support for the courts from a distinct outside source: intrastate actors such as state governors and Congress, societal mobilization, or the armed forces. The first path is most effective; the second is costly and challenging to organize; the last is itself dangerous to democracy.