The world still judges Lincoln by his Gettysburg Address. Now, it may judge Donald Trump the same way—but with strikingly different results. On Saturday, Trump spoke to supporters in the small Pennsylvania town where, a century and a half before, Americans met in battle. It was a speech that, as much as any in this campaign, offered the very best of Trump, underscoring why so many Americans are drawn to his candidacy. It also offered the very worst.