Would Franklin Roosevelt approve of Social Security? The question seems absurd. After all, Social Security is considered the New Deal’s signature achievement. It distributes nearly $800 billion a year to 56 million retirees, survivors and disabled beneficiaries. On average, retired workers and spouses receive $1,839 a month — money vital to the well-being of millions. Roosevelt would surely be proud of this, and yet he might also have reservations. Social Security has evolved into something he never intended and actively opposed.

It has become what was then called “the dole” and is now known as “welfare.” This forgotten history clarifies why America’s budget problems are so intractable.

When Roosevelt proposed Social Security in 1935, he envisioned a contributory pension plan. Workers’ payroll taxes (“contributions”) would be saved and used to pay their retirement benefits. Initially, before workers had time to pay into the system, there would be temporary subsidies. But Roosevelt rejected Social Security as a “pay-as-you-go” system that channeled the taxes of today’s workers to pay today’s retirees. That, he believed, would saddle future generations with huge debts — or higher taxes — as the number of retirees expanded....