The Constitution guarantees the right of association and of private property. Unions violate both rights. They exercise extortion tactics (sanctioned by the unconstitutional Labor Relations Act) to force employers to hire only union members and pay unions for the privilege of providing jobs that would otherwise not exist without them.
Then they force would-be employees to be a party to this extortion and pay the union for the privilege of having a job.
There is only one appropriate response to union "organizers." It involves an overwhelming and terminal use of violence. The fact that the good people of the US are using gentler methods of extermination of these vermin is a tribute to our goodness of the people they victimize.