In these circumstances the norm should be a small budget deficit, or even a surplus. But that is not the case now. In 2018, the deficit was 3.9 percent of G.D.P., compared with an average deficit of 2.1 percent of G.D.P. over the previous 70 years.

Even so, the current deficit is less worrisome than its trajectory. The Congressional Budget Office estimates that, under current law, the deficit will increase to 4.6 percent of G.D.P. in 2023. That projection is based on the plausible but optimistic assumption of continued economic growth and no major military conflict.

Because of these deficits, the government debt held by the public will rise to 85 percent of G.D.P. in 2023, reaching the highest level since 1947, the Congressional Budget Office says. And if current law remains unchanged, the debt will keep rising as a percentage of G.D.P., eventually reaching levels never seen in the United States. That is simply not sustainable.

What is to be done? Perhaps the wisest words on this topic come from an old New Yorker cartoon. In it, the president’s advisers are huddled around his desk. They summarize the situation this way: “Our deficit-reduction plan is simple, but it will require a great deal of money.”

If we are not going to saddle future generations with ever-increasing government debt, we need to find a great deal of money. That means either spending less or taxing more.

I would prefer to curb spending. For example, to prevent Social Security’s funding shortfall from enlarging the government debt, we could slowly increase the age of eligibility. The government would still provide a safety net for the very old, but others would have to keep working or use their savings to pay for an earlier retirement.

But I recognize that my preferences might not reflect those of the body politic. Many people want a more expansive government to address such problems as the rising cost of health care and the explosion of student debt. Doing so would require higher taxes.