Make propaganda illegal again.
The U.S. Information and Educational Exchange Act of 1948 (Public Law 80-402), popularly called the Smith–Mundt Act, is the basic legislative authorization for propaganda activities conducted by the U.S. Department of State, sometimes called "public diplomacy". The act was first introduced by Congressman Karl E. Mundt (R-SD) in January 1945 in the 79th Congress. It was subsequently passed by the 80th Congress and signed into law by President Harry S. Truman on January 27, 1948.
The Smith-Mundt Modernization Act of 2012, which was contained within the National Defense Authorization Act for Fiscal Year 2013 (section 1078 (a)) amended the United States Information and Educational Exchange Act of 1948 and the Foreign Relations Authorization Act of 1987, allowing for materials produced by the State Department and the Broadcasting Board of Governors (BBG) to be available within the United States.[1][2]
https://en.wikipedia.org/wiki/Smith%E2%80%93Mundt_Act