The earliest case on record, namely the Philadelphia shoemakers’ strike case in 1806,[29] charged two offences; one was a combination to raise wages, the other a combination to injure others; both offences were declared by the judge to be forbidden by the common law.  To the public at large the prosecution seemed to rest solely upon the charge that the journeymen combined to raise wages.  The defense took advantage of this and tried to make use of it for its own purposes.  The condemnation of the journeymen on this ground gave rise to a vehement protest on the part of the journeymen themselves and their friends.  It was pointed out that the journeymen were convicted for acts which are considered lawful when done by masters or merchants.  Therefore when the next conspiracy case in New York in 1809 was decided, the court’s charge to the jury was very different.  Nothing was said about the illegality of the combinations to raise wages; on the contrary, the jury was instructed that this was not the question at issue.  The issue was stated to be whether the defendants had combined to secure an increase in their wages by unlawful means.  To the question what means were unlawful, in this case the answer was given in general terms, namely that “coercive and arbitrary” means are unlawful.  The fines imposed upon the defendants were only nominal.

A third notable case of the group, namely the Pittsburgh case in 1815, grew out of a strike for higher wages, as did the preceding cases.  The charges were the same as in those and the judge took the identical view that was taken by the court in the New York case.  However, he explained more fully the meaning of “coercive and arbitrary” action.  “Where diverse persons,” he said, “confederate together by direct means to impoverish or prejudice a third person, or to do acts prejudicial to the community,” they are engaged in an unlawful conspiracy.  Concretely, it is unlawful to “conspire to compel an employer to hire a certain description of persons,” or to “conspire to prevent a man from freely exercising his trade in a particular place,” or to “conspire to compel men to become members of a particular society, or to contribute toward it,” or when persons “conspire to compel men to work at certain prices.”  Thus it was the effort of the shoemakers’ society to secure a closed shop which fell chiefly under the condemnation of the court.

The counsel for the defense argued in this case that whatever is lawful for one individual is lawful also for a combination of individuals.  The court, however, rejected the arguments on the ground that there was a basic difference between an individual doing a thing and a combination of individuals doing the same thing.  The doctrine of conspiracy was thus given a clear and unequivocal definition.

Another noteworthy feature of the Pittsburgh case was the emphasis given to the idea that the defendants’ conduct was harmful to the public.  The judge condemned the defendants because they tended “to create a monopoly or to restrain the entire freedom of the trade.”  What a municipality is not allowed to do, he argued, a private association of individuals must not be allowed to do.