If we apply this reasoning universally, should any sovereign nation engaged in war receive indefinite support as long as they are willing to fight? Historical

If we apply this reasoning universally, should any sovereign nation engaged in war receive indefinite support as long as they are willing to fight? Historical cases, such as the U.S. in Vietnam or the Soviet Union in Afghanistan, suggest that prolonged external backing can lead to drawn out conflicts with high costs and unintended consequences. Is there a point at which the costs/economic, political, or humanitarian of indefinite support outweigh the intended benefits? How do you think such a threshold be determined? I think one should _at least_ consider alternatives pathways to achieve a resolution.