I don't think the UN can be reformed sufficiently--can't get there from here. It's a council of governments and a giant uberNGO, but it lacks both many of the routine administrative organs of a government, as well as a philosophical basis for acting as a government; it has no legitimacy to expand beyond what it is today.

It was LarryJ, if I recall, who once explained that conservatives object to the UN's authority over the US because American citizens have no voice at the UN--as a council of governments, it's all Senate and no House, so to speak. And that's one issue on which I can clearly see the conservative point of view, and agree with it. I don't want the UN to become the government over me, either. I'd rather start from scratch with the intention of creating a represenative government.

I've mused about what forms of government people might adopt if they had the freedom to colonize lots of planets and set up lots of specialized societies. In that scenario forms such as theocracy aren't so objectionable, because there are alternatives, as long as you protect the right of free emigration. Along the way, though, some of the planets, such as "sector capitols", will have to be more cosmopolitan, and tolerate diversity, in the interests of trade and commerce and government. On those planets, what other form of government would you choose for a heterogenous society, but a clone of the American system? Representative democracy, with institutional chex-n-balances, is the best general-purpose recipe for governing we know, and that's the one we'll reach for in both the space colonization and Earth government scenarios. So I just wouldn't fret about some nightmare global tyranny arising. Relax. It'll be America writ large.