The Legal Services Corporation Act authorizes petitioner Legal Services Corporation (LSC) to distribute funds appropriated by Congress to local grantee organizations providing free legal assistance to indigent clients in, inter alia, welfare benefits claims. In every annual appropriations Act since 1996, Congress has prohibited LSC funding of any organization that represented clients in an effort to amend or otherwise challenge existing welfare law. Grantees cannot continue representation in a welfare matter even where a constitutional or statutory validity challenge becomes apparent after representation is well under way. Respondents--lawyers employed by LSC grantees, together with others--filed suit to declare, inter alia, the restriction invalid. The District Court denied them a preliminary injunction, but the Second Circuit invalidated the restriction, finding it impermissible viewpoint discrimination that violated the First Amendment.

Held: The funding restriction violates the First Amendment. Pp. 5-15.

(a) LSC and the Government, also a petitioner, claim that Rust v. Sullivan, 500 U. S. 173, in which this Court upheld a restriction prohibiting doctors employed by federally funded family planning clinics from discussing abortion with their patients, supports the restriction here. However, the Court has since explained that the Rust counseling activities amounted to governmental speech, sustaining viewpoint-based funding decisions in instances in which the government is itself the speaker, see Board of Regents of Univ. of Wis. System v. Southworth, 529 U. S. 217, 229, 235, or instances, like Rust, in which the government uses private speakers to transmit information pertaining to its own program, Rosenberger v. Rector and Visitors of Univ. of Va., 515 U. S. 819, 833. Although the government has the latitude to ensure that its own message is being delivered, neither that latitude nor its rationale applies to subsidies for private speech in every instance. Like the Rosenberger program, the LSC program was designed to facilitate private speech, not to promote a governmental message. An LSC attorney speaks on behalf of a private, indigent client in a welfare benefits claim, while the Governments message is delivered by the attorney defending the benefits decision. The attorneys advice to the client and advocacy to the courts cannot be classified as governmental speech even under a generous understanding of that concept. In this vital respect this suit is distinguishable from Rust. Pp. 5-8.

(b) The private nature of the instant speech, and the extent of LSCs regulation of private expression, are indicated further by the circumstance that the Government seeks to control an existing medium of expression in ways which distort its usual functioning. Cases involving a limited forum, though not controlling, provide instruction for evaluating restrictions in governmental subsidies. Here the program presumes that private, nongovernmental speech is necessary, and a substantial restriction is placed upon that speech. By providing subsidies to LSC, the Government seeks to facilitate suits for benefits by using the State and Federal Judiciaries and the independent bar on which they depend for the proper performance of their duties and responsibilities. Restricting LSC attorneys in advising their clients and in presenting arguments and analyses to the courts distorts the legal system by altering the attorneys traditional role in much the same way broadcast systems or student publication networks were changed in the limited forum cases of Arkansas Ed. Television Commn v. Forbes, 523 U. S. 666, and Rosenberger v. Rector and Visitors of Univ. of Va., supra. The Government may not design a subsidy to effect such a serious and fundamental restriction on the advo