This. There is a very big difference between unifying tribes and unifying nations. W.r.t. the Commonwealth, even then the Commonwealth fell apart for three maj

This. There is a very big difference between unifying tribes and unifying nations. W.r.t. the Commonwealth, even then the Commonwealth fell apart for three major reasons, viz., the so-called Swedish Deluge, the Khmelnytsky Uprising and the abuse of the liberal political system by the nobility with foreign meddling playing a major role. The second was ethno-religious in nature and the third driven in part by conflicting interests. (Indeed, the Polish Enlightenment differed from the Enlightenment in the West precisely because it dealt with the problem of too much or misallocated freedom.) The dispersion of military might among private armies (in some cases the sizes of private armies of wealthy magnates rivaled the royal armies in size) coupled with conflicting interests prevented the Commonwealth from being able to mount a coherent and unified defense against Russian, Prussian and Austrian dismemberment, and ultimately destruction, of the state. And while it lasted, even though the Commonwealth was a vastly freer place that permitted the peaceful coexistence of many different ethnic groups and religions, it nonetheless was held together by a dominant group with a dominant ethos, viz., the Polish nobility. In other words, empires suffer from tension when they impose their will on the constituting nations, but they also suffer from a lack of coherent and unified interests among its members. The EU suffers from both. On the one hand, you have the federalist impulse wishing to beat member states into submission by asserting a "soft" German dominance over the continent against the wishes of its members. On the other hand, you have the same politicians possessed by this impulse maintaining that they respect the individuality and alleged sovereignty of each state. We respect cultural differences, but we completely ignore them when gerrymandering policies. All members are equally important, but our policies favor the interests of certain members over others and have in place a voting system that privileges might over collaboration. The migrant crisis undermines the Schengen Zone. The Greek crisis undermines the euro zone. Nord Stream undermines the idea of common energy policy. The Ukrainian crisis undermines the idea of common foreign policy. It's easy to wallow in shallow sentiments in the absence of crises, but it is precisely during crises that the substance of such unions is revealed. The truth is that the EU is creeping dangerously toward a point of no return. Instead of serving as a platform for nations to find common ground and collaborate for mutual benefit, it has contributed to the opposite through its incompetence, its arrogance and its Brummagem unity concealing the real political interests at play.