None of the Trump Jr. allegations suggest conduct analogous to levying war against the United States, which generally requires some use of force in an attempt to overthrow the government. Nor does it amount to adhering to the enemy; for purposes of the Treason Clause, an enemy is a foreign nation or group with which the United States is in a state of war, either declared or actual. We are not in a state of war with Russia. In the 1950s, Julius and Ethel Rosenberg were executed for espionage, not treason, because the Soviet Union, although an implacable adversary, was not technically an enemy. We were formally at peace with the Soviet Union then, and we are formally at peace with Russia now.
So for purposes of American treason law, the details of Donald Trump Jr.’s relationship with Russia are irrelevant. He could be a paid foreign agent of Russia; he could take an oath of allegiance to Russia; he could even bug his father’s White House bedroom on behalf of Russian intelligence. None of those actions would amount to treason in the narrow sense that our Constitution defines it.