Democrats have become increasingly cognizant of the anger, but too often they’ve drawn the wrong conclusions. The answer certainly isn’t socialism. Middle-class voters currently presume that elites already control the government—so why would they want to give the bureaucracy any more power? Rather, Democrats need to become the party of justice. They need to demand accountability from bad actors—and point out where Republicans would give them a pass. They don’t need to castigate entire industries, as some might recommend. But when people make decisions that affect innocent bystanders—beating the drums for an ill-conceived war, making complicated financial instruments—they should be...