While I personally abhor the political leanings of unions, I respect the right of people to band together to form a union.

The Anti-Racketeering Act (Hobbs Act) of 1943 forbids the obstruction of interstate commerce by robbery or extortion. However, unions and union leaders are exempt from this act because the Supreme Court ruled that "the law simply doesn't apply when unions are seeking 'legitimate' union objectives."

United States v. Enmons, 410 U.S. 396 (1973), was a controversial United States Supreme Court case in which the Court held that violence, if carried out in furtherance of a labor union's objectives, does not violate the law according to the extortion and robbery provisions of the federal Anti-Racketeering Act of 1934 or the Hobbs Act.

The case involved a labor strike in which union members fired rifles at three utility company transformers, drained the oil from another, and blew up an entire company substation. The labor union in question was seeking a higher-pay contract and other benefits from their employer, the Gulf States Utilities Company. The Court decided that the International Brotherhood of Electrical Workers (IBEW) was immune from prosecution because their violent acts were in pursuit of a legitimate union objective.
When groups perceive themselves as being exempt from prosecution, we can expect them to push until there is push-back.

http://capitalresearch.org/wp-conten...ing-130926.pdf
http://en.wikipedia.org/wiki/United_States_v._Enmons