@Bix If concrete proof of that influence could be found, couldn't he be charged with treason and (if found guilty) executed?
@IrelandTorin
No. The crime of treason is only available for use in wartime. There are espionage laws that could be used against Trump, but they don't have a death penalty, like treason.
@Bix If I'm not mistaken, the US has something like five active wars at the moment. This is wartime.