In places like New York City the unions are easily able to stop the work of any private contractor. The private contractors know this and collaborate with the

In places like New York City the unions are easily able to stop the work of any private contractor. The private contractors know this and collaborate with the unions on ensuring that they are able to ensure that the contracts mandate union labor. This is not how most unions in the United States operate but they do operate this way in locations where the dominant political party has not changed for a hundred years, see NYC. It's rather condescending to indicate to someone that they don't understand what a union is. You should research a little bit more before you assume that unions aren't able to influence private companies that employ them when negotiating contracts with local governments. It's simply wrong. I'm very familiar with these details because I had to do a detailed analysis of labor costs for the WMATA which has to negotiate with unions to operate the DC metro system.