It is a mistake to think that America's unions are in decline. Yes, the AFL-CIO is having its troubles.... Public sector unions, then, are not in decline at all. Indeed, they are extraordinarily powerful. They have many millions of members, they are loaded with money for campaigns and lobbying, and they have activists in virtually every political district in the country. No other interest groups can match their potent combination of money, manpower, and geographic dispersion. Ask Arnold Schwarzenegger. He has proposed reforms (of public employee pensions, of teacher tenure) that California's public sector unions fiercely oppose. And they have...