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 is
designed merely to undermine the profitable relations which the employer
had developed with his customers. These expectancies are advantages
enjoyed by established businesses over new competitors and are usually
transferable and have market value. For these reasons they are now
recognized as property in the law of good-will and unfair competition
for customers, having been first formulated about the middle of the
nineteenth century.

The first case which recognized these expectancies of a labor market was
Walker _v._ Cronin,[35] decided