“Politicians, like diapers, should be changed often. And for the same reasons.” – Tom Blair

But Harvey himself, in a syndicated editorial from June 1994, credits the exact quote – “Politicians, like diapers, should be changed often. And for the same reasons.” – to Tom Blair, a longtime columnist for the San Diego Union-Tribune. Harvey likely got this attribution from a 1993 issue of Reader’s Digest in which the aphorism was excerpted with Blair’s byline.

https://marktwainstudies.com/the-apocryphal-twain/politicians-are-like-diapers/