Schenck vs. US

The First Amendment of the constitution guarantees that each person has the right to free speech. But the Supreme Court has restricted free speech that includes obscenities, libel, slander, words that incite violence or words that pose a threat to the rights of individuals or national security. You do not have the right to yell 'fire' in a crowded theater, as Justice Oliver Wendell Holmes pointed out in Schenck v. United States (1919), when the "circumstances are of such a nature as to create a clear and present danger."

Using this precedent, are Rush Limbaugh's comments protected under the 1st Amendment? Why or why not?