Four years ago, Joe Biden rehearsed for debates at a lectern in the basement of his Delaware home. Now, as president, he can pick a room at the White House, his retreat at Camp David, Maryland, or almost anywhere else in the country. But as much as the atmospherics have changed around Biden — whether it's the room he's in, the ups and downs of the economy or the outbreak of wars in Eastern Europe and the Middle East — his preparations for rematch debates with former President Donald Trump promise to be remarkably consistent with his 2020 sessions. Trump...