Under Article III, Section 3, of the Constitution, any person who levies war against the United States or adheres to its enemies by giving them Aid and Comfort has committed treason within the meaning of the Constitution. The term aid and comfort refers to any act that manifests a betrayal of allegiance to the United States. If a subversive act has any tendency to weaken the power of the United States to attack or resist its enemies, aid and comfort has been given.
Fearing a civil liberties backlash and "bad public relations" for the Obama administration, Homeland Security Secretary Jeh Johnson refused in early 2014 to end the secret U.S. policy that prohibited immigration officials from reviewing the social media messages of all foreign citizens applying for U.S. visas.