The Logan Act (1 Stat. 613, 18 U.S.C. § 953, enacted January 30, 1799 (1799-01-30)) is a United States federal law that details the fine and/or imprisonment of unauthorized citizens who negotiate with foreign governments having a dispute with the United States. It was intended to prevent the undermining of the government's position. The Act was passed following George Logan's unauthorized negotiations with France in 1798, and was signed into law by President John Adams on January 30, 1799. The Act was last amended in 1994, and violation of the Logan Act is a felony.
To date, only two people have ever been indicted for violating the Act's provisions. However, no person has ever been prosecuted for alleged violations of the Act. Wikipedia