The U.S. Supreme Court case Brown, Secretary of Defense, et al. v. Glines in 1979 revolved around the issue of free speech within military ranks and whether it was constitutionally protected under the First Amendment rights or could be limited by military regulations for maintaining order and discipline. The plaintiff, Captain Glines, challenged an Air Force regulation that required prior approval before circulating petitions on a base as he believed this violated his First Amendment rights to freedom of speech and assembly. However, the court ruled in favor of Brown (Secretary of Defense), upholding that such restrictions were necessary for maintaining good order and discipline within the military environment which is fundamentally different from civilian life due to its unique mission requirements. Therefore, while acknowledging that members do not surrender all their constitutional rights upon joining armed forces; these can be restricted reasonably considering national security interests.

In the dissenting opinion for Brown, Secretary of Defense, et al. v. Glines (1979), Justice Brennan argued that the majority's decision to uphold military regulations restricting service members' right to circulate petitions within a base was an overreach and violated First Amendment rights. He contended that these restrictions were not necessary for maintaining good order and discipline in the armed forces as claimed by the majority. Instead, he believed they represented an unwarranted intrusion into service members' free speech rights without sufficient justification or compelling government interest. Furthermore, he criticized the majority's reliance on Parker v Levy (1974) precedent which upheld broad deference to military authority in regulating its own affairs; instead arguing this case involved more direct infringement on constitutional freedoms unlike Levy where there was no clear suppression of protected expression.