In the 20th century, the United States built the most advanced infrastructure system ever — made up of highways, bridges, air and sea ports, rail and mass transit systems, dams and levees, and a modern electricity grid. Those investments put millions to work and fueled our economic growth, expanded our horizons, and made us the envy of the world. But in the years since, we’ve failed to keep up those investments, and we’ve moved from first in the world to middle of the pack.It’s time to restore our infrastructure through smart investments.