Logan Act

The Logan Act, enacted in 1799 and codified at 18 U.S.C. section 953, makes it a crime for a private citizen, without authorization from the U.S. government, to correspond or communicate with a foreign government in order to influence its conduct in disputes with the United States. It has periodically featured in controversies over unauthorized diplomacy. It’s referenced in connection with Michael Flynn, who as the incoming national security adviser discussed U.S. sanctions with Russian Ambassador Sergey Kislyak during the 2016 to 2017 transition.