With the comeback in financial markets this year, we probably should have seen it coming. But the headline rebound in first quarter growth to 3.2% reported Friday is still a pleasant surprise that shows again that the U.S. economy is remarkably resilient when government doesn’t get in the way.

The Keynesians who predicted an imminent recession are pointing out flaws in the GDP details, and they’re right that volatile categories like net exports (1.03%), inventory growth (0.65%) and state and local government (0.41%) contributed...