Most judges, lawyers, and scholars take it for granted that to charge a criminal defendant, the government needs only probable cause of guilt. But in fact, probable cause represents a choice, not a fixed element of our legal tradition.

This Article begins with the history of the probable cause standard. It presents novel evidence that many Founding-era American judges rejected the idea, urged by a group of English lawyers and judges a century earlier, that criminal charges require only a “probable ground for accusation.” Many insisted that grand jurors should be certain of a suspect’s guilt before returning an indictment, a charging standard that was well suited to the Founding generation’s anxiety about concentrations of power and their informal criminal trials. Probable cause gained traction as a charging standard in the United States in the late nineteenth and twentieth centuries, when the criminal trial gained the appearance of reliability. Grand juries and magistrates no longer needed to be certain of a suspect’s guilt because a trial jury would be. Or so it must have seemed at the time.

The puzzle is that the probable cause standard survived even after the rise of plea bargaining exploded this logic. This Article offers three explanations for probable cause’s survival as a charging standard. First, policymakers may not have valued certainty of guilt, or, for that matter, constraint on prosecution, as much as they once did. Second, “voluntary” guilty pleas may have provided—or appeared to provide—adequate certainty of guilt. Third, policymakers may have failed to examine the fit between plea bargaining and probable cause, making probable cause’s survival a matter of unreflective path dependence. But while these explanations are descriptively plausible, they are also normatively troubling. Worse, the probable cause standard exacerbates plea bargaining’s innocence problem and its propensity for prosecutorial control of criminal justice. The time has come to revisit it.