No he can't. He has already most likely talked to Pooty Poot and arranged acceptable talking points.
This is not small ball, to be sure. This is real politik. Both The Donald and Pooty are aware and in agreement as to who the real enemy is. Donald will rattle his sword, talk tough, and Pooty will act offended and maybe make some small threat back. The end.
My confidence on that is high.
The condemnation and shrill will be intense. POTUS takes no action the shrill gets louder. and he is weakened. Thinking as you are above some agreement made how to show publically. Also remember, Putin can not look weak either.
Can be done, as you say real politk here