Can a newspaper refuse to run a letter or advertisement?
Yes, newspapers do have a First Amendment right to refuse letters to the editor and ads. Since they are privately owned entities whose editors have editorial control, they are free to promote whatever political, social or economic view they wish.
The U.S. Supreme Court addressed the issue of editorial control and freedom of the press in 1974 in the case Miami Herald Publishing Co. v. Tornillo, 418 U.S. 241. This case concerned a Florida political candidate who brought suit against The Miami Herald pursuant to the state’s “right-to-reply” statute after the paper refused to print the candidate’s reply to editorials critical of him. The statute in question required a newspaper to provide equal space to a political candidate to reply to any criticism of the candidates’ personal character or official record printed by the newspaper. The Supreme Court found the statute to be unconstitutional in that it violated the First Amendment right to a free press.
The Court wrote:
“A newspaper is more than a passive receptacle or conduit for news, comment, and advertising. The choice of material to go into a newspaper, and the decisions made as to limitations on the size and content of the paper, and treatment of public issues and public officials — whether fair or unfair — constitute the exercise of editorial control and judgment. It has yet to be demonstrated how governmental regulation of this crucial process can be exercised consistent with First Amendment guarantees of a free press as they have evolved to this time.”