The principle of "proportional retaliation,"

Ira Strauss, director of the Atlantic Council's Institute for War and Peace and senior advisor to the Atlantic Council, a major research organization, published an article titled "Equality for Ukraine" on January 15, in which he advocated that the U.S. and European countries allow the Ukrainian military to attack Russian housing and infrastructure facilities as well.
  As long as Ukraine articulates the principle of "proportional retaliation," in which any attack on Russian territory would cause destruction on the Russian side to the extent equivalent to the damage suffered by Ukraine, Russia would not choose the path of bold escalation, such as a direct attack on NATO, but would be inclined to respond by curbing its aggression against Ukraine, he said. This proportionate retaliation would be a response that the Russian people would not be willing to accept.
  This proportional retaliation would make the Russian people aware of the fear and truth, and could be an opportunity for Putin's ouster and civil war. It could also be expected to hasten the end of the war. We hope that the leaders of the United States and the West will consider this paper and decide that the framework of support for Ukraine should be significantly changed to give Ukraine the ability to attack on Russian territory.