This thread is to brainstorm how a world government could actually take hold and what form it might take -- and, just as important, how these can translate into interesting story hooks.
Well...hrm.
The thing is that, often enough, in science fiction a world government is one of three things: they're formed as a result of extraordinary pressure either internal or external that forces everyone to come together either for the sake of survival or "because we fucking said so and we have the guns so shut the fuck up" (your UNSC's). They're formed as a result of extraordinary plenty, like post-scarcity shit and are intended to be more utopia set-ups that you proooobably shouldn't look too closely at because that's not really the point (your Federations). Or they're formed as the result of extraordinary author laziness because they can't be assed to make more than one nation for one planet.
Your Mass Effects, no matter how hard they try to subvert that shit.
They're somewhat less intrinsically horrible than regional mega-nations. Y'know what I mean, the kind that are like "Let's put all the brown people together. Okay now all the Asians. Now everyone on an island. Now America on it's own except bigger. Now the
other kind of brown people. And the EU I guess". But I think that's generally a product of the fact that you're not supposed to pick them apart too terribly much (unless the narrative exists to pick them apart) because, when you get right down to it, they just don't
work. Parliamentary, dictatorial, tbh it doesn't really matter. People have distinct national and regional identities. People generally don't appreciate being funneled into a huge slush.
Like, imagine trying to make a mega-nation that encompassed both Iran and Saudi Arabia and didn't immediately implode into infighting and catered to the needs and beliefs of both. Now Pakistan and India. Now the Koreas. Now imagine trying to do all that shit
simultaneously while also unifying South America and all of Africa and here's where we hit the problem.
Just 'cause it's common doesn't necessarily mean it's good yo. And sure there are ways to bring it about with a new-ish twist that prompts discussion (everyone's engineered strains of a planet-wide Hive, everyone's communist cyborgs, the world's turned hypercapitalist and is a monopoly, etc). But it's better to couch them in terms of broader ideas imo rather than try to unpack the sausage.
Because the history and the fine details are going to be kinda stupid and some level of offensive no matter which way you slice it. Unless you're flat out acknowledging that it's more of a One World Order in name only and still rife with pretty deep divisions.