In the hands of a body with moral authority, it can be a weighty and substantial tool. In the hands of the the United Nations Security Council, it is yet another vapid expression of futility.
Even in a case so unambiguous as the legitimacy of Bashar Assad's presidency, China and Russia vetoed a resolution demanding that he step down. Of course, the UN has no power to enforce such a resolution ... at least not without the will and power of the United Status armed forces. But if it had possessed even the tiniest bit of moral standing, perhaps such a resolution would have been taken seriously. Since the UN has no moral standing, it may be just as well that the resolution failed to be adopted. The Devil of Damascus cannot defy a declaration that has never been made.