Bangladesh, Jan. 24 -- If the world manages to navigate the coming decade without catastrophic collapse, historians may look back on the second Trump administration with a mixture of disbelief and relief. Relief that the international system endured, and disbelief that such strain was placed upon it by the actions of a single leader wielding unparalleled military, economic, and political power. Donald Trumps return to the White House has already produced a pattern of behavior that signals a deeply unstable period ahead-one marked by aggressive foreign policy, domestic repression, and a willingness to challenge long-standing norms among allies and adversaries alike.

At the center of global anxiety lies a question that would once have seem...