Abuse of power and bribery is what that the Ukraine case is all about. You could call it extortion, also. Mulvaney, Pompeo, and at least eight more national security officials are potential co-conspirators, unless they come clean with the full transcript of the phone call. Obstruction of justice applies to anyone who is not forthcoming with documents or testimony to this case. Guiliani is pretty well guilty of at least that, and probably a whole lot more. Campaign finance laws seem to have been broken pretty much everywhere along the line. As to the unilateral decision to withdraw US forces from a critical position in the war against Isis, that would be dereliction of duty, and since the people that gain the most in that situation are Russia, Isis, Syria, and Iran, I would say that is aiding and abetting the enemy, and just a hint of treason. Treason is actually debatable because technically you have to be in a real declared war for that to apply, but it can easily be seen as espionage, as well as the couple of times he has given away classified information to the Russians. Anybody remember that hilarious time he invited the Russian spy chief to the oval office? Then we have about ten instances of obstruction of justice from the Mueller Report (that the sitting president can't be indicted for) but that doesn't mean it can't be considered "high crimes and misdemeanors". I think the dereliction of duly, by not defending the constitution from all enemies foreign (Russia, Isis, Syria, Iran) and domestic ( himself and the Republican leadership) is the most salient potential charge. He has already called parts of the constitution phony, and has been violating the emoluments clause daily. In truth, he is virtual saturated in high crimes and misdemeanors.
