Yes i think UN is able to enforce regulations and restrictions on rest of the world simply because it is backed up by many powerful nation including some of the strongest nations. UN nations usually come together at a particular point by thinking what is the best solution for the problem.
When the United Nations was originally formed, member nations with power and resolve occupied important roles in the organization's leadership. Today, this is no longer the case. Delegates from insignificant nations sit on committees and decry the US or another country for an action of strength. Further, the sanctions and peace-keeping efforts made by the UN today are laughable. The United Nations does not further the cause of world peace.