The U.S. Supreme Court case Kleindienst v. Mandel (1971) revolved around the issue of whether the United States Attorney General had the authority to deny a temporary nonimmigrant visa to a foreign national on ideological grounds, specifically due to their communist beliefs. Ernest Mandel, a Belgian journalist and Marxist scholar, was invited by American academics for lectures but was denied entry into the U.S because he advocated communism - an ideology contrary to that of America's democratic principles. The court ruled in favor of Richard Kleindienst, then acting Attorney General, stating that as long as there is "a facially legitimate and bona fide reason," it is within executive discretion under immigration law to refuse visas based on political belief or activity without violating First Amendment rights of those who wished to hear him speak.

In the dissenting opinion for Kleindienst v. Mandel, Justice Marshall argued that the majority's decision failed to adequately protect First Amendment rights. He contended that when a government seeks to restrict an individual's right of free speech on grounds of national security or public order, it must provide compelling evidence supporting its claim. In this case, he believed such evidence was lacking and thus disagreed with denying Mandel entry into the U.S based solely on his political beliefs and affiliations. Furthermore, he emphasized that constitutional protections should not be compromised even in matters related to immigration policy or foreign affairs. The denial of a visa due to ideological disapproval infringes upon American citizens' rights as well since they are deprived from hearing differing viewpoints directly from their source.