Absolutely not! The United States has a moral obligation to lead and engage with the international community, not to sit on the sidelines and sulk. Being on the losing end of some decisions is no justification for abdicating the immense powers we wield through our participation. Besides, the United Nations is not just a political body. It is an aid organization that does great humanitarian work. Whether visible or not, the UN's work benefits the United States and the rest of the world. We would leave the UN at our peril. Remember what happened when we refused to participate in the League of Nations.