William J. Brennan, Jr., United States v. Robel — Concurrence
“ Even if the statute is not overbroad on its face because there may be 'defense facilities' so essential to our national security that Congress could constitutionally exclude all Party members from employment in them-the congressional delegation of authority to the Secretary of Defense to designate 'defense facilities' creates the danger of overbroad, unauthorized, and arbitrary application of criminal sanctions in an area of protected freedoms and therefore, in my view, renders this statute invalid. ”
