What the dry figures don’t convey is the degradation of government at the agency and program level. This is occurring, though documenting its extent is hard. Francis Collins, head of the National Institutes of Health, estimates that the agency’s budget has lost nearly 25 percent of its purchasing power in the last decade. NIH used to approve one of three grant proposals; the ratio now is one of six. Presumably, younger researchers suffer most. Some public-health problems (say, resistance to existing antibiotics) may be underfunded.

The Internal Revenue Service blames budget cuts and reduced staffing for delays in mailing refunds and responding to taxpayer questions. In 2014, only about two-thirds of callers got through to an agent, and waiting times averaged nearly 20 minutes. (In 2004, nearly 90 percent got through, with typical waiting times of 2 1/2 minutes.) The national parks have also been hit. Since 2010, their funding has decreased 12 percent in inflation-adjusted dollars, and the backlog of deferred maintenance has topped $11 billion, says the National Parks Conservation Association, an advocacy group.

We are allowing demographics to determine national priorities. Nowhere is this more apparent than defense, which is scaling back (the Army alone is cutting an estimated 120,000 active-duty troops from its wartime peak) just when foreign threats seem to be rising. So demographics even shape global strategy.