Modern government is organized on “clear law,” the false premise that by making laws detailed enough to take in all possible circumstances, we can avoid human error. And so over the last few decades, law has gotten ever more granular. But all that regulatory detail, like sediment in a harbor, makes it hard to get anywhere. The 1956 Interstate Highway Act was 29 pages and succeeded in getting 41,000 miles of roads built by 1970. The 2012 transportation bill was 584 pages, and years will pass before workers can start fixing many of those same roads. Health-care regulators have devised 140,000 reimbursement categories for Medicare—including 12 categories for bee stings and 21 categories for “spacecraft accidents.” This is the tip of a bureaucratic iceberg—administration consumes 30 percent of health-care costs.

Legal detail skews behavior in ways that are usually counterproductive. Why did VA officials regularly falsify waiting times? Bureaucratic metrics required them to meet waiting time deadlines—or else they would forfeit a portion of their pay. Why didn’t they just do a better job? Compliance was basically impossible: Congress had mandated more VA services but only modestly expanded resources. Undoubtedly, better efficiency could have been squeezed out of available resources, but that would require liberating VA officials from civil-service straitjackets so they could manage other civil servants. Rigid bureaucracy, not the inexcusable dishonesty of VA officials, was the underlying cause of the VA scandal.

“Clear law” turns out to be a myth. Modern law is too dense to be knowable. “It will be of little avail to the people,” James Madison observed, “if the laws be so voluminous that they cannot be read, or so incoherent that they cannot be understood.” The quest for “clear law” is futile also because most regulatory language is inherently ambiguous. Dense rulebooks do not avoid disputes—they just divert the dispute to the parsing of legal words instead of arguing over what’s right. Indeed, legal detail often undermines the regulatory goal. “The more exact and detailed a rule, the more likely it is to open up loopholes, to permit by implication conduct that the rule was intended to avoid,” Judge Richard Posner observed.

What’s the alternative? Put humans back in charge. Law should generally be an open framework, mainly principles and goals, leaving room for responsible people to make decisions and be held accountable for results. Law based on principles leaves room for the decision-maker always to act on this question: What’s the right thing to do here?

Until recent decades, law based on principles was the structure of most public law. The Constitution is 10 pages long and provides basic precepts—say, the Fourth Amendment prohibition on “unreasonable searches and seizures”—without trying to define every situation. The recent Volcker Rule regulating proprietary trading, by contrast, is 950 pages, and, in the words of one banker, is “incoherent any way you look at it.”