President Joe Biden’s proposed infrastructure legislation has the political class seemingly locked in a debate about what “infrastructure” means. Biden and Democratic leaders—backed by a majority of the U.S. population—believe that “infrastructure” is more than just roads and bridges and encompasses all the structures that help modern society function. Their new bill reflects that understanding, including improvements to water pipes and the electrical grid, universal broadband access, charging stations for electric vehicles, physical upgrades to schools and universities, and—perhaps most innovatively—home care for the elderly and disabled, support for families with children, and expanded access to health care. Republican elected...