[jeremyarussell]

That would require all the world governments to agree on what a patent is and what it can protect. As it stands now the nations don't agree much on anything, let alone something as important as patent law.

Edit: clarification

[lttlrck]

Its more than that I think, international laws require internation courts so all countries would have to relinquish control of intellectual property to a central authority and world patent court. It would create as many problems as it creates.