 A fourth legal argument is that comprehensive campaigns violate federal anti-trust law.As unions work with other organizations, it is claimed that they form, essentially, a commercial enterprise which seeks to economically dominate the market much in the same way that a monopoly does.In support of this claim, critics note that the Supreme Court has read the Sherman, Clayton and Norris-LaGuardia acts in such a way that unions are held exempt from federal antitrust laws but only so long as a union acts in its own self-interest and does not lose its primary character as a labor union by combining with other, non-labor groups or organizations.