of the combination. It has been urged in some judicial opinions that
in matters of boycotts, strikes, etc., the law cannot go into the
motive; this argument obviously proves too much, for it is no more
easy to examine motives in the criminal law, and this is done all
the time. A homicide, for instance, will vary in all degrees between
justifiable guilt or manslaughter up to murder in the first degree,
according to the motive which prompted the act. It is really no more
difficult, and the reported cases do not show it to be any more
difficult, to consider the motive behind a combination of men or the
motive inspiring a series of related acts. The real trouble comes only
in the Federal anti-trust act, because the machinery of this clumsy
statute, a bill in equity, imposes upon judges the duty of finding the
facts.

This doctrine of conspiracy is so old in England that I am unable to
trace it to its source. From the wording of repeated early statutes
it would seem that they recognized this law of conspiracy as already
existing and merely applied it to new forms, such as, for instance,
the combination of masons, carpenters, and guilds, just mentioned. It
is, perhaps, not to us important whether it is originally based on
common law or these early statutes, for these statutes are quite early
enough to have passed into the common law of England, and consequently
into the common law in this country. Moreover, early statutes merely
express the common law; therein lies their significance. Now, many
State laws and constitutions, as well as most State courts, recognize
that the common-law statutes of England existing at least before 1775,
if not 1620,[1] are common law in the States of this Union. In a
general way, any statute that antedates the time of our settlement we
took over as part of our common law.