One reason to be skeptical: it’s becoming increasingly difficult to see the payoff from spending more. In the study on road conditions, five of the states that spend the most per mile have among the worst roads. That includes, in addition to Rhode Island and California, New York, whose roads rank fifth-worst though it spends the eighth most, and New Jersey, with the third-highest expenditures and the tenth-worst roads. Meantime, states like Georgia, Tennessee, and Minnesota somehow manage to have among the best roads in America with just average spending per mile.

Some states have tried to defend their poor records on roads by arguing that local conditions make their infrastructure harder to maintain. But state policies clearly play a part in overspending and poor quality. New York, California, and New Jersey all have prevailing-wage laws that require contractors on their building programs to pay essentially the equivalent of union wages, raising costs by at least 10 percent. For decades, New York State has taken revenues from gas taxes designated for roads and used some of it to pay for the inflated compensation of transportation bureaucrats, a way to offload some of the expense of these generous salaries and benefits from the state budget at the cost of road maintenance. New Jersey maintains a vast and expensive bureaucracy that includes both a Department of Transportation and a Turnpike Authority.

Increasingly, one gets the sense that states are spending on problems of their own creation.