Where the eighties witnessed a revolution was in a totally new use made of the doctrine of conspiracy by the courts when they began to issue injunctions in labor cases.  Injunctions were an old remedy, but not until the eighties did they figure in the struggles between labor and capital.  In England an injunction was issued in a labor dispute as early as 1868;[31] but this case was not noticed in the United States and had nothing whatever to do with the use of injunctions in this country.  When and where the first labor injunction was issued in the United States is not known.  An injunction was applied for in a New York case as early as 1880 but was denied.[32] An injunction was granted in Iowa in 1884, but not until the Southwest railway strike in 1886 were injunctions used extensively.  By 1890 the public had yet heard little of injunctions in connection with labor disputes, but such use was already fortified by numerous precedents.

The first injunctions that attained wide publicity were those issued by Federal courts during the strike of engineers against the Chicago, Burlington, & Quincy Railroad[33] in 1888 and during the railway strikes of the early nineties.  Justification for these injunctions was found in the provisions of the Interstate Commerce Act and the Sherman Anti-Trust Act.  Often the State courts used these Federal cases as precedents, in disregard of the fact that there the issuance of injunctions was based upon special statutes.  In other cases the more logical course was followed of justifying the issuance of injunctions upon grounds of equity.  But most of the acts which the courts enjoined strikers from doing were already prohibited by the criminal laws.  Hence organized labor objected that these injunctions violated the old principle that equity will not interfere to prevent crime.  No such difficulties arose when the issuance of injunctions was justified as a measure for the protection of property.  In the Debs case,[34] when the Supreme Court of the United States passed upon the issuance of injunctions in labor disputes, it had recourse to this theory.

But the theory of protection to property also presented some difficulties.  The problem was to establish the principle of irreparable injury to the complainant’s property.  This was a simple matter when the strikers were guilty of trespass, arson, or sabotage.  Then they damaged the complainant’s physical property and, since they were usually men against whom judgments are worthless, any injury they might do was irreparable.  But these were exceptional cases.  Usually injunctions were sought to prevent not violence, but strikes, picketing, or boycotting.  What is threatened by strikes and picketing is not the employer’s physical property, but the relations he has established as an employer of labor, summed up in his expectancy of retaining the services of old employes and of obtaining new ones.  Boycotting, obviously, has no connection with acts of violence against physical property, but