that the president of another country is very smart in the way he is reacting to sanctions against his government because of--the intelligence operation that may have accounted for the President-Elect even being the President-Elect. This shows the least amount of interest possible for a situation in which US national security might have been breached by a foreign power and should be deeply concerning.
Some people might suspect that Putin has no need to retaliate because he is already confident that a Trump Administration will treat him more "fairly". Word might be that this is because Trump is, in fact, compromised. He doesn't have to confirm it with his cavalier behavior. But he simply doesn't seem to care.