What about the
United Nations?

Three United Nations (UN) Resolutions were passed on Tibet in the 1960s. They were passed prior to 1972 when the People's Republic of China (PRC) became a member of the United Nations. 

Before 1972, China's seat at the UN was occupied by the nationalist government of Taiwan, who were anti-Communist and supported resolutions on Tibet.

Since 1972, when the PRC took over the seat at the UN, it has been virtually impossible to raise the issue of Tibet at the UN General Assembly or in the Security Council because China is a permanent member of the Security Council and has the right to use its veto. Any mention of Tibet at the UN will be vetoed by China. Therefore, most governments do not bother to raise the issue of Tibet at the UN.