What is the current state of the US Supreme Court opinion on First Amendment freedom of speech?

In 1940 the United States Supreme Court in Thornhill v. State of Alabama, 310 U.S. 88, said at page 101, 60 S.Ct. 736, at page 744, 84 L.Ed. 1093: 'The freedom of speech and of press guaranteed by the Constitution embraces at the least the liberty to discuss publicly and truthfully all matters of public concern without previous restraint or fear of subsequent punishment.'

In 1945 the high court stressed that the First Amendment attempts to secure 'the widest possible dissemination of information from diverse and antagonistic sources.' (Associated Press v. United States, 326 U.S. 1, 20, 65 S.Ct. 1416, 1424, 89 L.Ed. 2013.)