In his latest act of trading 5 Taliban from Gitmo for a deserter, this act alone is worthy of impeachment but if we include everything he has done over the last 5 years there is more than enough cause to move forward with an impeachment trial.
The dictionary stats treason as -
Treason
noun
1.
the offense of acting to overthrow one's government or to harm or kill its sovereign.
2.
a violation of allegiance to one's sovereign or to one's state.
3.
the betrayal of a trust or confidence; breach of faith; treachery.
I believe Obama has acted in a way that fulfills each of these definitions of treason.