OCTOBER TERM, 1975 Per Curiam 424 U. S. to be truly or optimally "effective." Moreover, the invasion of privacy of belief may be as great when the information sought concerns the giving and spending of money as when it concerns the joining of organizations, for "[flinancial transactions can reveal much about a person's activities, associations, and beliefs." California Bankers Assn. v. Shultz, 416 U. S. 21, 78-79 (1974) (POWELL, J., concurring). Our past decisions have not drawn fine lines between contributors and members but have treated them interchangeably. In Bates, for example, we applied the principles of NAACP v. Alabama and reversed convictions for failure to comply with a city ordinance that required the disclosure of "dues, assessments, and contributions paid, by whom and when paid." 361 U. S., at 518. See also United States v. Rumely, 345 U. S. 41 (1953) (setting aside a contempt conviction of an organization official who refused to disclose names of those who made bulk purchases of books sold by the organization). The strict test established by NAACP v. Alabama is necessary because compelled disclosure has the potential for substantially infringing the exercise of First Amendment rights. But we have acknowledged that there are governmental interests sufficiently important to outweigh the possibility of infringement, particularly when the "free functioning of our national institutions" is involved. Communist Party v. Subversive Activities Control Bd., 367 U. S. 1, 97 (1961). The governmental interests sought to be vindicated by the disclosure requirements are of this magnitude. They fall into three categories. First, disclosure provides the electorate with information "as to where political campaign money comes from and how it is spent by the candidate" " in order to aid the voters in evaluating those 77 H. R. Rep. No. 92-564, p. 4 (1971).