A police officer needs probable cause to make an arrest. But, almost always, he needs no more. In this way, an arrest may be constitutionally reasonable even if it is entirely unreasonable by any plausible moral or instrumental measure. Indeed, the Court has upheld even an arrest that it termed a “gratuitous humiliation” and a “pointless indignity.” In this Article, I examine what accounts for the Court’s prevailing methodological approach to Fourth Amendment reasonableness, and I evaluate whether the Court’s reasoning withstands scrutiny. Specifically, I trace the Court’s methodology back to a particular conception of the legality principle, whereby formalistic measures are crafted around suspicion of guilt and are treated as exclusive. I offer contrary reasons, however, to conclude that the legality principle’s chief purpose (as a safeguard against the arbitrary exercise of executive discretion) is better served by a two-ply constitutional test that would demand both probable cause and general reasonableness. That is, I submit that probable cause might work best as a special supplement to otherwise-relevant qualitative considerations (and not as a special substitute). To support this claim, I focus narrowly on one particular qualitative consideration that probable cause has almost completely cannibalized. That consideration is dignity. It is not my purpose, however, to see the Fourth Amendment reoriented around dignity. Dignity matters, but neither it nor probable cause (nor anything else) is all that matters. I rely upon dignity as a placeholder for any of the many qualitative considerations that a quantitative proxy for constitutional reasonableness has unjustifiably ignored.