The bill, pending in both chambers, would make it a crime for anyone to "knowingly and willfully" disseminate information "prejudicial to the safety or interest of the United States." Stone, a law professor at the University of Chicago and chair of the ACS Board, says that while the measure "may be constitutional as applied to government employees who unlawfully leak such material to people who are unauthorized to receive it, it would plainly violate the First Amendment to punish anyone who might publish or otherwise circulate the information after it has been leaked. At the very least, the act must be expressly limited to situations in which the spread of the classified information poses a clear and imminent danger of grave harm to the nation."
The clear and present danger standard has been a central element of our First Amendment jurisprudence ever since Justice Oliver Wendell Holmes Jr.'s 1919 opinion in Schenk v. United States. In the 90 years since, the precise meaning of ‘clear and present danger' has evolved, but the animating principle was stated brilliantly by Justice Louis D. Brandeis in his 1927 concurring opinion in Whitney v. California. The founders ‘did not exalt order at the cost of liberty,' wrote Brandeis; on the contrary, they understood that ‘only an emergency can justify repression. Such must be the rule if authority is to be reconciled with freedom. Such ... is the command of the Constitution. It is, therefore, always open to Americans to challenge a law abridging free speech and assembly by showing that there was no emergency justifying it.'
In December, Professor Stone testified before the U.S. House Judiciary Committee on the bill, which is dubbed the "Securing Human Intelligence and Enforcing Lawful Dissemination Act," or SHIELD Act. His written testimony before the committee is available here.