Incidentally, I've just read the funniest sentence in the whole series.
Hang on—is it just me, or is Ireland not independant in the Potterverse? There's no Irish Minister of Magic in the Top Box at the Quidditch World Cup and Cornelius Fudge presents the Cup to the Irish team. But even more damningly, the headquarters of the British and Irish Quidditch Leagues are clearly stated to be in the Ministry of Magic in London! What's the deal, J.K.?
Although, when you think about it, this may not be what I'm thinking. What if magical!Ireland became independant of magical!Britain long before 1922—or was never subjugated by British wizardry at all—and this apparent union was a peaceful and voluntary one, like the European Union? Really, you would think there would be more of a postnationalist movement in the wizarding world than in the Muggle world, given that wizards are a small global subculture that exists in isolation from the Muggle world. After all, bigotry in the Potterverse seems to be mostly limited to anti-Muggle and anti-part-human/non-human sentiment (with a few exceptions, like a crack on Angelina's hair). But you don't really see that in the books. Of course, the impetus for the peaceful union of Europe (an completely unprecedented event in human history) was World War II, and although the rise of Grindelwald was going on at around the same time, one doesn't get the sense that it brought magical!Europe to its knees like the first half of the twentieth century did to Muggle Europe.
(Hang on—what happened to the wizards who were drafted in WWII, and all the other various Muggle wars? Did they just dodge the draft? Or did the Ministry pull strings? Man, can you imagine Winston Churchill being told that the hundreds of incredibly powerful magic-users in Britain were just sitting this one out? I guess the Minister at the time might have been able to convince him with the argument that if British wizards joined in, German ones would too, and it would be Muggle communities that suffered. Though I can't believe that Hitler—who was, after all, a big fan of the occult—would have accepted that argument, especially as the war was coming to its end and he was willing to do anything to prevent defeat.)