President Biden’s debate meltdown vividly demonstrated that cognitive and other skills decline with age. But a combination of demographic trends and federal fiscal irresponsibility make it imperative that America make better use of its senior citizens’ productive skills. Not all old people lose it like Mr. Biden. Henry Kissinger was writing important books well into his 90s, and Konrad Adenauer served ably as West Germany’s chancellor until he was 87. Several frequent contributors to these pages are older than Mr. Biden, including Lance Morrow (84), Phil Gramm (82), Joseph Epstein (87) and me (83).

The American population is aging rapidly. In the middle of the last century, there were almost eight working-age (16 to 65) Americans for everyone over 65. I estimate that by 2050 that ratio will shrink to 3 to 1. Hence the need for occupationally capable older citizens to work longer.