The 70-plus years since 1941 have seen a vast increase in the welfare safety net and governance by cooperation among big units — big government, big business, big labor — that began in the New Deal and gained steam in and after World War II. I immodestly offer my own “Our Country: The Shaping of America from Roosevelt to Reagan.”

The original arrangements in each 76-year period became unworkable and unraveled toward its end. Eighteenth-century Americans rejected the Colonial status quo and launched a revolution, then established a constitutional republic.

Nineteenth-century Americans went to war over expansion of slavery. Early-20th-century Americans grappled with the collapse of the private-sector economy in the Depression of the 1930s.

We are seeing something like this again today. The welfare state arrangements that once seemed solid are on the path to unsustainability.