The obvious point of comparison is Ruth Bader Ginsburg. By hanging onto power far past the point of political and actuarial prudence, she ended up costing the Democrats their most precious seat on the Supreme Court, imperiling the right to abortion and shifting the balance of power to conservatives. That wasn’t great, but Feinstein is guilty of a more grievous sin. Until the very end, Ginsburg could actually do her job, writing meaningful opinions. Feinstein sadly isn’t able to even say “aye” when her party needs her.

Feinstein’s condition spurs a question that looms over American politics for obvious reasons, given the age—for the moment, at least—of the top candidates in the next presidential election: When does the beneficent version of gerontocracy give way to the destructive version of it? Admirable reasons for handing power to senior citizens almost inevitably become the justification for their never relinquishing it. The cult of experience becomes the cult of indispensability.

[A reasonable question, but in Foer’s telling, the answer is: only when it interferes with Democrats’ agenda. It’s not just a gerontological issue either, given John Fetterman’s obvious impairments. Both parties have been guilty of refusing to let go of impaired pols, but for now this is clearly a Democrat issue — especially in the White House. — Ed]