evidence: Joe Biden launched his candidacy for president in 2019 with the words "we are in the battle for the soul of this nation." He was right. And though it wasn’t obvious at first to many Democrats, he was the best person to wage that fight. He was a genial but also shrewd campaigner for the restoration of what legislators call "regular order." [...] Biden has in many ways remade himself as president. He is no longer the garrulous glad-hander I met when I first covered Congress more than four decades ago. He’s still an old-time pol, to be sure, but he is now more focused and strategic; he executes policies systematically, at home and abroad. As Franklin Foer writes in "The Last Politician," a new account of Biden’s presidency, "he will be remembered as the old hack who could." [...] I hope Biden has this conversation with himself about whether to run, and that he levels with the country about it. It would focus the 2024 campaign. Who is the best person to stop Trump? That was the question when Biden decided to run in 2019, and it’s still the essential test of a Democratic nominee today.