Does our support for Ukraine in their defensive war against Russia’s invasion qualify as a “just war?” Thomas Aquinas insisted that for a war to be just it must be conducted by a sovereign government, and the war must be for a just cause, and it must be fought by soldiers who fight to accomplish something that is good. Of course, innocent people die in all wars and no army is comprised of entirely noble soldiers, so war crimes will be committed by all nation’s armies in some instances. When is the cost of supporting Ukraine too much for the stated goals in defeating Russia?