A federal license to main: when unions begin knocking heads, the NLRB starts slapping wrists - if that. (National Labor Relations Board's response to labor union violence)

UNION VIOLENCE is far more widespread in the U.S. than public opinion realizes. The National Right to Work Committee estimates that almost 6,000 violent incidents have occurred during strikes since 1975. But this is less surprising than it might appear since federal labor relations policy implicitly permits some workers to use violence against other workers. Thanks to the rulings of the National Labor Relations Board, a man's right to sell his labor is often at the mercy of whether other men feel that sale will damage their bargaining positions.

When they do, mayhem can…