He’s running—or so it would seem. Former Vice President Joe Biden has been making the rounds for his American Promise Tour, promoting (among other things) his new memoir, Promise Me Dad: A Year of Hope, Hardship, and Purpose, which centers around the death of his son, and his plans for the future. Naturally, the book is a hit. In the last week and a half, Newsweek has run two articles pitching a single-term Biden presidency to restore normalcy to American politics—one by Matthew Cooper titled, “Joe Biden Can Beat Trump in 2020, But Will the Democratic Party Let Him Run?,”...