This holding was possible because California's constitution contains an affirmative right of free speech which has been liberally construed by the Supreme Court of California, while the federal constitution's First Amendment contains only a negative command to Congress to not abridge the freedom of speech. The Supreme Court rejected the shopping center's argument that California's free speech right amounted to a "taking" of the shopping center under federal constitutional law.
The vote to uphold the California decision was unanimous, although three justices disagreed with part of the reasoning in Justice William Rehnquist's opinion for the majority. Justices Thurgood Marshall, Byron White, and Harry Blackmun filed separate concurring opinions.
Because of the Pruneyard case, people who visit shopping centers in California may regularly encounter people seeking money or attention for various causes, including charitable solicitations, qualifying petitions for amendments to the state constitution, voter registration drives, and sometimes a beggar. In turn, many shopping centers have posted signs to explain that they do not endorse the views of people exercising their right to free speech, and that if patrons do not give them money, the speakers will go away.
Although 39 other states have free speech clauses in their constitutions that look like California's — indeed, California borrowed its clause from a similar one in the New York Constitution — at least 13 of those states have declined to follow California in extending the right of free speech into private shopping centers. In refusing to follow Pruneyard, the state supreme courts of New York and Wisconsin both attacked it as an unprincipled and whimsical decision. Only New Jersey, Colorado, and Massachusetts have followed California, albeit with some reservations.
In the two decades since, the Supreme Court of California has become much more conservative, especially after three liberal justices (including Chief Justice Rose Bird) were removed by the electorate in 1986 for their opposition to the death penalty.
In the 2001 Golden Gateway decision, a 4-3 majority of the Court significantly narrowed Pruneyard by holding for a variety of reasons that California's free speech right does not apply to private apartment complexes — yet, they also refused to overrule Pruneyard. Thus, California's right of free speech in private shopping centers still survives.
Naturally, the shopping center industry strongly "detests" the Pruneyard decision; shopping centers have regularly imposed restrictions on unwanted solicitors and appealed the resulting legal cases in the hope of convincing the California judiciary that Pruneyard should be overturned, or at least limited. Since Golden Gateway, decisions by the intermediate Courts of Appeal have generally limited the scope of the Pruneyard rule to the actual facts of the original case. For example, starting in 1997, the parking lots of many Costco warehouse club stores in California became sites of conflict involving a large number of political activist groups who had gradually become aware of their rights under Pruneyard. In 1998, Costco's management imposed several restrictions, including a complete ban on soliciting at stand-alone stores, a rule that no group or person could use Costco premises for free speech more than 5 days out of any 30, and the complete exclusion of solicitors on the 34 busiest days of the year.
In 2002, these restrictions were upheld as reasonable by the Court of Appeal for the Fourth Appellate District, and the Supreme Court of California denied review. Costco's stand-alone stores lacked the social congregation attributes of the multi-tenant shopping center at issue in Pruneyard. As for the restrictions on the stores in shopping centers, they were held to be reasonable because Costco had developed a strong factual record at trial which proved that hordes of unwanted solicitors had significantly interfered with its business operations — they had damaged its reputation, obstructed access to its stores, and traumatized Costco employees.
In 2007, the Supreme Court of California confronted the Pruneyard decision once more, in the context of a complex labor dispute involving San Diego's Fashion Valley Mall (currently owned by Simon Property Group) and the San Diego Union-Tribune. On December 24, 2007, a 4-3 majority of a sharply divided court once again refused to overrule Pruneyard, and instead, ruled that under the California Constitution, a union's right of free speech in a shopping center includes the right to hand out leaflets urging patrons to boycott one of the shopping center's tenants. Justice Ming Chin, in his dissent joined by Justices Marvin Baxter and Carol Corrigan, expressed his sympathy with several of the most common critiques of the Pruneyard decision: "Pruneyard was wrong when decided. In the nearly three decades that have since elapsed, jurisdictions throughout the nation have overwhelmingly rejected it. We should no longer ignore this tide of history. The time has come for us to forthrightly overrule Pruneyard and rejoin the rest of the nation in this important area of the law. Private property should be treated as private property, not as a public free speech zone.