Moved to action by a widely felt need to sponsor independent sources of broadcast programming as an alternative to commercial broadcasting, Congress set out in 1967 to support and promote the development of noncommercial, educational broadcasting stations. A keystone of Congress' program was the Public Broadcasting Act of 1967, Pub. L. 90-129, 81 Stat. 365, 47 U. S. C. § 390 et seq., which established the Corporation for Public Broadcasting, a nonprofit corporation authorized to disburse federal funds to noncommercial television and radio stations in support of station operations and educational programming. Section 399 of that Act, as amended by the Public Broadcasting Amendments Act of 1981, Pub. L. 97-35, 95 Stat. 730, forbids any "noncommercial educational broadcasting station which receives a grant from the Corporation" to "engage in editorializing." 47 U. S. C. § 399. In this case, we are called upon to decide whether Congress, by imposing that restriction, has passed a "law . . . abridging the freedom of speech, or of the press" in violation of the First Amendment of the Constitution.