I'm proceeding pretty well on Regent with a huge Earth map as the English (started in Northern France) against the max # of AI opponents. I've got all of Europe, about half of Asia, and about a third of Africa toward the end of the Industrial Era, and about a 2-3 tech lead on the Ottomans (Australia), China (Brazil) and Spain (East Africa and a lot of Asia), and ten or so minor civs.
My question is, how does one avoid a Diplomatic defeat (or victory, for that matter) when the Diplo victory is enabled and someone can build the UN? I've made a lot of enemies, and if I need to take any AI city that's building the UN I will, but can I build it myself and then just never hold a vote?