Infrastructure comes in all shapes and sizes: roads, rails, and highways; miles of drinking water and wastewater pipes; power stations and the endless transmission lines that crisscross the country. But while infrastructure enables services that are essential to us, there have always been dividing lines over how we handle infrastructure policy. There is healthy debate over what level of government bears responsibility for which physical assets, and what we call different kinds of infrastructure.

Until recently, these discussions have been limited to transportation spending reauthorizations and early campaign promises. But the past year has brought that debate closer to the forefront of policy discussion.