In the United States, unions can engage in vandalism, extortion, and even outright violence including murder. And it's 100% legal. In 1973, the US Supreme Court ruled on a case named United States v Emmons. that unions can engage in all of these activities, as long as it's to further a legitimate union cause. A bill was offered in 1995 to end the practice but it failed. It's been offered every year since but the union backed democrats have killed the legislation every year.
If anyone in America but unions would commit these acts, they would be subject to some of the toughest laws ever enacted, the RICO Statute. (Racketeer Influenced and Corrupt Organizations Act) The RICO Act allows law enforcement to charge people who order these illegal acts to be commited, to face prosecution. Unless you are a union of course.
Individual union members can be charged with the crime but not the union or it's leaders that order it committed. The fact is that individual members are rarely prosecuted for committing crimes during labor disagreements, as documented by the Cato Institute. From 1975 to 1998, there were 8,799 such incidents recorded by the The National Institute for Labor Relations Research (NILRR). Of those cases, there were 258 convictions or about 3%.
Currently in the city of Philadelphia, there is a prime example of Supreme Court approved intimidation being demostrated against a private business concern that uses non-union labor. The Pestronk brothers,Matthew and Michael Pestronk, have felt the power of the unions unfettered by the law. The brothers bought an old building to restore into affordable luxury apartments.
Since the project is a private one, and not a government project, the Pestronk brothers use non-union labor. The unions decided to make an example of them before other major projects decided, they too, would not use union help. But in truth 40% of their project is being completed by union workers.
The electrical union submitted the winning bid for the contract by making some concessions to make their costs lower. Other unions chose to submit bids 50% higher than other bidders and then use intimidation, vandalism, and violence to force their way in. They didn't count on the brothers taping their activities and posting them on the Internet. Public opinion swung against the unions and the Pestronk brothers have prevailed.
With union membership reaching all time lows, unions will likely increase their use of these tactics, immune from prosecution. That's why U.S. Congressman Paul Broun has written abill, overriding the Supreme Court decision. It's unlikely to even get read on the senate floor as long as Harry Reid and the democrats are in power.