It has much to do with the way a country is made up. Germany for example has a very multipolar history, and the federal system takes this into account.

Its funny however how size does not necessarely mean too much in this regard, just look at Switzerland and Austria, even though regarding Austria I have to say that I consider the strong federal make up of the country a quite large waste of money. I dont oppose the federal principle but we simply have one administration level too much, its all bloated up a bit for the 8 mio people we are and when you take into account that with the EU just another level is being established.

I think the basic precondition to get a federal state running is that the states that make up the federal construct support the whole concept also in daily life. Just look at Belgium, even though you might counter that Belgium hardly qualify as federal state anymore...

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"Every country gets the cuisine it deserves"