What is the best place to start?
The problem is I really have four starting points, or perhaps I have five starting points–fear, surprise, ruthless efficiency, etc….
First, I would have to be even more rash than Charles le Temeraire, last duke of sovereign Burgundy, to opine about classical Dutch history with Jan de Vries in the room, but let me do so to point out that this session’s topic, "political union", is a vague and sketchy concept. The political union of the strongest power in 17th century Europe, the seven United Provinces of the Netherlands, was made up of the components. First, there was a talk shop in the Hague–which had rather less power than is currently assembled in Brussels and Strasbourg. Second, the same guy, the Prince of Orange, was nearly always the stadthouder, the chief executive, of all seven provinces. Third, one of the provinces, Holland, was 60% of the total, and so if consensus was not reached could threaten to go it alone and do what was necessary–but when it did so take down names and have a long memory of who had played ball and who had not.
Nevertheless, that was enough of a political union to transform seven provinces into a 17th century European great power, powerful enough to rule the seas and make everyone–including Louis XIV–fear it on land. The most memorable piece of Samuel Pepys’ diary about Restoration London is his lament one night, as he watched the fleet he had spent so much time trying to build burning on the Thames Estuary, that it seemed to him that: "The Devil shits Dutchmen." That was enough political union for the seven United Provinces of the Netherlands. Would that be enough for Europe today? I don’t know. But I do know that a "political union" is a very elastic concept.
Second there are the worries in the classical political tradition that a democratic political union on the scale of Europe is impossible. Aristotle believed there were no good democracies. Democracies were ridden by faction–so much so that politics devolved into a combination of street fights and purges. And if you did manage to get everyone together in the Assembly without their maiming each other beforehand, they would act fairly randomly, and fairly irrationally. They would decide today that they should execute every adult male in the recaptured city of Mytilene–even the demos–because the demos had been unwise enough to follow the aristoi when they had rebelled and tried to join affinity with Sparta during the Peloponnesian war.
Then, after what must have been an incredibly furious night by the Mytilenian ambassadors in Athens accompanied by lots of bags of gold to make sure the right people spoke in the Assembly on the following day, they reverse themselves. They promptly send off another trireme with an order not to kill every adult male in Mytilene. Faction-ridden, irrational, prone to aggressive militaristic war (because the demos would vote for a raiding expedition–you had the promise of plunder if you were in the fleet, plus regular wages while you were in the fleet). Democracies, Aristotle and company said were very bad news.
What you had to have instead was, ideally, politeia: a republic of mixed governmental principles with a strong aristocratic admixture in which, if I may give a Montesquieuian reading to Aristotle, the ruling passion was virtue. But a republic has to be small: people have to see and be seen as practitioners of the kind of virtuous public-spirited behavior that you can get in a well ordered, not-very-democratic-but-nevertheless-free, city-state politeia. Aristotle said you can keep this going–for a while, if you’re lucky to have a good starting setup–but only at the level of a city-state, nothing larger.