There is a consensus that the US should substantially raise its level of infrastructure investment. Economists and politicians of all persuasions recognise that this can create quality jobs and provide economic stimulus without posing the risks of easy-money policies in the short run. They also see that such investment can expand the economy’s capacity in the medium term and mitigate the huge maintenance burden we would otherwise pass on to the next generation.

The case for infrastructure investment has been strong for a long time, but it gets stronger with each passing year, as government borrowing costs decline and ongoing neglect raises the return on incremental spending increases. As it becomes clearer that growth will not return to pre-financial-crisis levels on its own, the urgency of policy action rises. Just as the infrastructure failure at Chernobyl was a sign of malaise in the Soviet Union’s last years, profound questions about America’s future are raised by collapsing bridges, children losing IQ points because of lead in water and an air traffic control system that does not use GPS technology.

The issue now is not whether the US should invest more in infrastructure but what the policy framework should be. There are five key questions.