 Kleinfeld was the author of the unanimous panel decision of "Morse v. Frederick", holding that a student who put up a banner supposedly supporting drug legalization was exercising his freedom of speech protected by the First Amendment, and the school principal acted unconstitutionally in suspending him.The school board appealed the decision to the Supreme Court, which heard the case on March 19, 2007.The Supreme Court, in a 2007 majority opinion authored by Chief Justice John Roberts, reversed Kleinfeld's ruling and ruled that the First Amendment does not protect in-school student speech advocating illegal drug use.