This is most likely a Logan act violation. But no one has ever been charged for it
Well, then.
Time to dust it off and use it!
Time to test the law.
Found these at wikipedia:
Only two indictments have ever been handed down under the Logan Act. The first occurred in 1803 when a grand jury indicted Francis Flournoy, a Kentucky farmer, who had written an article in the Frankfort Guardian of Freedom under the pen name of “A Western American.” In the article, Flournoy advocated a separate nation in the western part of the United States that would ally with France. The United States Attorney for Kentucky, an Adams appointee and brother-in-law of Chief Justice John Marshall, went no further than procuring the indictment of Flournoy, and there was no further prosecution of the Kentucky farmer. The purchase of the Louisiana Territory later that year appeared to cause the separatism issue to become moot, and the case was abandoned.[2][10]
In 1852, Jonas Phillips Levy became the second and, to date the last, person to be indicted under the Logan Act. Levy, an American merchant and sailor who was living in Mexico at the time, had acquired a grant to build a railway across the Isthmus of Tehuantepec, the narrowest point across Mexico. Secretary of State Daniel Webster had been pressuring Mexico to accept a treaty that would allow a different group of American businessmen to build the railway. Levy wrote a letter to Mexican President Mariano Arista urging him to reject Webster’s proposed treaty, prompting Webster to seek an indictment against Levy for violating the Logan Act. Federal prosecutors were forced to dismiss the case after Arista refused to hand over the original copy of the letter, depriving them of the evidence they needed to convict Levy.[3]
But never a conviction. Sounds like john f’n kohn-heinz-kerry would be a good place to start though. :-)