So of course there was a Mexico. Of course it was pretty similar to Mexico IRL. And because of sheer inertia, Mexico has existed as an independent nation ever since. But it hasn't stayed the same; the world has moved on, and the butterflies have turned it into the Grand Principality of Mexico.
The G.P. of Mexico 101
Why? Originally, this was the space-filling Empire of Mexico. After awhile, it evolved into a Bonapartist space-filling empire (on the lines of the Second Empire, which was run by a Habsburg); after that, into an ideologically Bonapartist empire; and after that, once reactionary Prussia had evolved into revolutionary Pomerania, into the G.P. of Mexico that you see here today.- Who? Almost all the possible permutations of the Moorish ethnoreligious colonial hierarchy, with the Muslim varieties greatly reduced, under the charismatic rule of the House of Sansinger and its forest of bayonets.
- What? At one point, the UCNA's nemesis; at this point, its quirky miniboss antagonist.
- Where? Mexico and more. The G.P. of Mexico controls enough land to its south to have built the Mexican Canal, for instance.
- When? Like almost everything in the New World, the G.P. of Mexico is a child of the Great Realignment - specifically that part in the 1790s, when the Moorish colonial empire imploded. From that point, despite more and more serious turmoil than IRL Mexico was ever diverse enough to experience, it's managed to survive to the present day.