Credit: Joshua Roberts/Bloomberg

President Donald Trump’s debut budget proposal is a stark declaration of war on the future of the American economy that substitutes a curious mix of ideology and blind nostalgia for any effort to think critically about the actual needs of a 21st-century nation.

The war starts with reducing spending — even though an aging population, plus the government’s role in inherently labor-intensive activities like education and long-term care, militates overwhelmingly in favor of a somewhat larger role for the state. But it continues with the priorities Trump set for where the remaining cash gets spent.

The picture that emerges is overwhelmingly one of nostalgia — more money for men with guns, less money for education, caring, and pointy-headed science. But nostalgia is not memory. The midcentury economy Trump yearns for was, almost by definition, less technologically advanced and educationally intensive than today’s.

But it was an extraordinarily forward-looking time. Propelled by the imperatives of Cold War competition, the United States made investments on […]