It's the revolution of rising expectations again.

Watching Donald Trump last week, I thought of Alexis de Tocqueville, the French political philosopher whose "Democracy in America," published in the 1830s, remains the most insightful study of our national character. But it was de Tocqueville's other masterpiece, "The Old Regime and the French Revolution" (1856), that came foremost to mind. In it, he outlined what we now call the "revolution of rising expectations" — a concept highly relevant to today's presidential campaign.

The French revolution presented a paradox, de Tocqueville wrote. Before the revolution, prosperity was on the rise; and yet, it wasn't enough to prevent the revolution. Why? The answer, de Tocqueville argued, was that the first taste of prosperity had whetted people's appetites for more — and when these raised expectations were not met, there was a backlash. Existing ideas and institutions were discredited. There was a power vacuum. Change became chaos.