It was revealed in the French Canadian newspaper La Presse that the Canadian government has informally proposed to the United Nations that they move their headquarters to the Montreal Old Port. The new site would essentially occupy a cluster of artificial islands between the downtown core and Habitat 67.
Detailed architectural plans have already been developed as shown in these images. These new installations would cost almost the same as the proposed $1.9 billion renovation of the Manhattan complex. They would also expect to save $790 millions per year in maintenance and the 65 acres site would be much bigger than the 7 17 acres currently occupied in Manhattan and would thus provide space for many of the UN-associated NGOs that are scattered all over the New York City area.
Finally, there is the additional advantage of improved security since the access to this new UN-city would be much easier to control.
The political consequence of such a move have not been covered in the article. I think that it is safe to assume that they would be quite significant.