Dalai Lama's Proposed Visit To Taiwan - Who Is China To Oppose It?

The Chinese government is upset with His Holiness Dalai Lama's proposed visit to Taiwan. The spokesperson of the Chinese government has openly conveyed his government's displeasure to the global media, saying that his government "resolutely opposes" Dalai Lama's proposed visit to Taiwan (the country which China considers to be a part of its own).

Now, what locus standi does the Chinese government have in opposing Dalai Lama's visit to Taiwan? Taiwan is a sovereign country (no matter what China thinks about it), and it has full right to invite any person on its soil. And Dalai Lama is also by no means answerable to the Chinese government for his actions. Then from where does China get the right to express displeasure over the issue, in the first place?