It is not clear it was smart. But it was not treason.
pRES_ _ENT Obama would have had to betray Kenya or Indonesia.
Politicians “betray” countries all the time.
Big fricken deal. Nixon, for example, derecognized (betrayed) Taiwan when he recognized China. If it takes such “betrayal” to end a dumb policy that needlessly poked Russia in the eye, that is the price that should paid.