The first major piece of legislation that affected labor unions was the
Sherman Antitrust Act of 1890. The law forbade any "restraint of
commerce" across state lines, and courts ruled that union strikes and
boycotts were covered by the law. This was ironic since the Sherman Act
had been passed by liberal reformers hoping to curb the abuses of
business cartels and monopolies, not to crack down on unions.
Hope this helps! Took me awhile to type!
