Under Articles 5 and 6 of the United Nations Charter a nation can either be suspended or expelled from the United Nations General Assembly for persistently violated the Principles contained in the present Charter may be expelled from the Organization by the General Assembly upon the recommendation of the Security Council.
The US and other nations should sponsor an amendment to the UN Charter to allow nations to be suspended or removed from the Security Council for persistently violating the Principles contained in the present Charter and for consistently acting outside the realm of peaceful Nations. Once this amendment has been passed and ratified, Russia should be removed from the Security Council (which would allow the UN to move ahead with resolving conflicts in Syria and the Ukraine).