After making a great deal of noise about the importance of the social safety net during his 2016 campaign, Mr. Trump held standard Republican positions on such issues as work requirements for recipients of Medicaid, which Mr. Biden has reversed. It somehow never occurred to Mr. Trump or anyone in his orbit to allow Americans to purchase health insurance plans from the online marketplace outside the pointlessly narrow open enrollment window, as Mr. Biden did months ago. Why is Mr. Biden having more success carrying out some of his predecessor’s policies? Certainly Mr. Trump’s fabled étourderie and his inability to staff a cabinet with qualified officials sympathetic to what was ostensibly his agenda are a part of the story. A more interesting question, though, is where the indignation from would-be opponents of moderate protectionism and realism in foreign policy has gone. Would Mr. Biden’s broken promises regarding deportations be less excusable if he, too, were in the habit of calling immigrants revolting names? Metaphysics, said the philosopher F.H. Bradley, is the finding of bad reasons for things we believe instinctively. It might well be that the essence of Mr. Biden’s presidency will be finding wholesome-sounding reasons for doing all the things — some wicked, others sensible, a handful plainly laudable — that his predecessor had attempted out of malice or indifference.