Crises can drive change, but sometimes it takes two crises to cement a transformation. Alone, the Great Depression ushered in the New Deal, roughly tripling U.S. federal spending as a share of output. But it took World War II to push federal spending much higher, solidifying the role of the state in the U.S. economy. If federal interventions such as the creation of the interstate highway system felt natural by the mid-1950s, it was the result of two compounding shocks, not a single one.