in matters of governing importance. New York Times Co. v. Sullivan, 376 U. S. 254, 270 (1964). “For speech concerning public affairs is more than self-expression; it is the essence of self-government.” Garrison v. Louisiana, 379 U. S. 64, 74-75 (1964). “The maintenance of the opportunity for free political discussion to the end that government may be responsive to the will of the people and that changes may be obtained by lawful means, an opportunity essential to the security of the Republic, is a fundamental principle of our constitutional system.” Stromberg v. California, 283 U. S. 359, 369 (1931). The fact that the message is proposed as a paid advertisement does not diminish the impregnable shelter afforded by the First Amendment. See New York Times Co. v. Sullivan, supra, at 271.
Of course, not even the right of political self-expression is completely unfettered. As we stated in Cox v. Louisiana, 379 U. S. 536, 554 (1965):
“The rights of free speech and assembly, while fundamental in our democratic society, still do not mean that everyone with opinions or beliefs to express may address a group at any public place and at any time. The constitutional guarantee of liberty implies the existence of an organized society maintaining public order, without which liberty itself would be lost in the excesses of anarchy.”
Accordingly, we have repeatedly recognized the constitutionality of reasonable “time, place and manner” regulations which are applied in an evenhanded fashion. See, e. g., Police Department of Chicago v. Mosley, 408 U. S. 92, 98 (1972); Grayned v. City of Rockford, 408 U. S. 104, 115 (1972); Cox v. Louisiana, supra, at 554-555; Poulos v. New Hampshire, 345 U. S. 395, 398 (1953); Cox v. New Hampshire, 312 U. S. 569, 575-576 (1941); Schneider v. State, 308 U. S. 147, 160 (1939).