An act against the Constitution is void; an act against natural equity is void.

Otis is asserting a hierarchy of authority: written constitutional principles and the higher claims of “natural equity” (natural law/justice) set limits on what legislatures may validly enact. In this view, a statute that contradicts fundamental constitutional arrangements is not merely bad policy but legally ineffective (“void”). By adding “natural equity,” he also implies that even if a measure is procedurally enacted, it can still lack legitimacy if it violates basic justice. The formulation anticipates later Anglo-American arguments for judicial review and for rights grounded in natural law, themes that became prominent in Revolutionary-era constitutional thought.