f a Wisconsin statute which authorized the
giving of publicity to labor disputes, declared peaceful picketing and
patrolling lawful, and prohibited the granting of injunctions against
such conduct to a controversy in which the matter at issue was the
refusal of a tiling contractor employing nonunion workmen to sign a
closed shop agreement unless a provision requiring him to abstain from
working in his business as a tile layer or helper should be eliminated.
Inasmuch as the enhancement of job opportunities for members of the
union was a legitimate objective, the State was held competent to
authorize the fostering of that end by peaceful picketing, and the fact
that the sustaining of the union in its efforts at peaceful persuasion
might have the effect of preventing Senn from continuing in business as
an independent entrepreneur was declared to present an issue of public
policy exclusively for legislative determination.[164]

The policy of many State legislatures in recent years, however, has been
to adopt legislation designed to control the abuse of the enormous
economic power which previously enacted protective measures enabled
labor unions to amass; and it is the constitutionality of such
restrictive measures that has lately concerned the Court. Thus, in
Railway Mail Association _v._ Corsi,[165] section 43 of New York's Civil
Rights Law which forbids a labor organization to deny any person
membership by reason of race, color, or creed, or to deny any member, on
similar grounds, equal treatment in designation for employment,
promotion, or dismissal by an employer was sustained, when applied to an
organization of railway mail clerks, as not interfering unlawfully with
the latter's right to choose its members nor abridging its property
rights, or liberty of contract. Inasmuch as it held "itself out to
represent the general business needs of employees" and functioned "under
the protection of the State," the union was deemed to have forfeited the
right to claim exemption from legislation protecting workers against
discriminatory exclusion.[166] Similarly approved as constitutional in
Lincoln Union _v._ Northwestern Co.[167] and American Federation of
Labor _v._ American Sash Co.[168] were State laws outlawing the closed
shop; and when labor unions invoked in their own defense the freedom of
contract doctrine that hitherto had been employed to nullify legislation
intended for their protection, the Court, speaking through Just