In the case of Amalgamated Food Employees Union Local 590 et al. v. Logan Valley Plaza, Inc., et al., in 1967, the U.S Supreme Court ruled that a shopping center could not prohibit peaceful picketing by union members on its property. The dispute arose when employees of a supermarket located within the shopping plaza protested against non-unionized labor practices and were subsequently barred from demonstrating within the premises by Logan Valley Plaza management citing trespassing laws. The court held that such prohibition violated their First Amendment rights to freedom of speech and assembly as it was deemed an equivalent public forum despite being privately owned due to its open invitation for public patronage and use. This landmark decision expanded constitutional protections into private spaces used for public purposes but has since been limited by subsequent rulings.

The dissenting opinion in the case of Amalgamated Food Employees Union Local 590 et al. v. Logan Valley Plaza, Inc., et al., argued that the majority's decision to allow union picketing on private property was a violation of the property owner's rights and an overextension of First Amendment protections. The dissenters contended that while freedom of speech is vital, it does not grant unlimited access to all venues for expression - particularly when those venues are privately owned properties where business operations could be disrupted by such activities. They also pointed out inconsistencies with previous court rulings which had upheld restrictions on picketing in similar contexts, arguing this represented an unjustified departure from established legal precedent.