First it was Great Britain, now it’s Spain: the devolution of once all-powerful nation states continues. On Monday, Spain’s Catalonia region’s autonomous parliament voted to secede from Spain by 2017, having won elections in September promising to do just that.

Why is Europe breaking up? And what does this mean for Spain? Let’s get super.

The cliff notes

Most of Europe lives under very different geopolitical conditions than the rest of the world, being dominated by American power through NATO and governed internally by the European Union.

This has created a wholly unprecedented period of European peace and stability, allowing political, social and economic experimentation that could not be tolerated in other environments.

So long as these experiments don’t threaten the fundamental conditions of Europe, they’ll be allowed to go forward.

But should any of them threaten the overriding order, the powers that be will strike back using whatever means they require.

It remains to be seen if Catalonia qualifies as a threat to the established order but the long odds are that it doesn’t and Spain may well soon be forced to bid farewell to wealthy Barcelona.

Alright, before we get to the specifics, we need to get the broad rules

From the fall of the Roman Empire until 1945, Europe was geopolitically chaotic and quite a murderous continent. For about a thousand years, from the Lombard Wars to World War II, Europeans had a startlingly high propensity to die a war.

This was because Europe lacked a policeman for that whole period. No one power was able to impose order on the continent; instead, a seemingly endless series of would-be hegemons rose, got ever so close and then were inevitably defeated by a coalition of enemies determined to keep the continent split up. Arguably the most secure of European nation states, Great Britain, recognized this condition and rather than try to overcome it set about trying to make it permanent.

This is what a multipolar international system looks like

“Multipolar” means there are varying powers of just about the same strength able to interact with one another. (That’s key to understanding history: although China was far more powerful than Europe for most of human history, it lacked the technological means to deploy that power to Europe.)

When a geopolitical environment is multipolar, uncertainty reigns. Nobody can be fully sure their neighbors have their best interests as heart: states prefer to arm themselves in case pushes turn to shoves. This can lead to long periods of stalemate, since everyone is worried about upsetting a delicate apple cart, but it does nothing to guarantee an ambitious upstart doesn’t decide they don’t like apples.

There are varying reasons why such leaders emerge: madmen gain power, technologies change (and thereby shift balances of power), states misread or miscalculate the geopolitical situation. The general point is this: when a region is multipolar, war is a viable means to make oneself more powerful. It’s a risky means but not an impossible one. And that makes war considerably more likely.

World War II was the last time this multipolar system failed in Europe. Prior to Hitler’s invasion of the Soviet Union in 1941, Europe was not neatly divided between Axis and Allies: rather it was divided between several European blocs that sought advantage over one another. This is best illustrated by the Nazi-Soviet alliance but in between there were Italian machinations, Spanish civil warring, Finnish side-switching, Yugoslav waffling and much more posturing as small powers sought to survive the power politics of big ones. Only with the invasion of the Soviet Union did the continent split firmly between two camps.

And that’s the condition it kept, with the Axis collapsing and giving way to Soviet and American power. With technology having advanced enough to allow both America and the Soviet Union the ability to keep and deploy power in Europe, and with European powers having exhausted themselves in their final, most murderous of multipolar wars, the continent remained split between Washington and Moscow, with nuclear weapons keeping the frontier frozen.

Rather than having a series of policemen, each wishing to impose their own system of law and order on everyone else, the firefight of World War II left only two. This made miscalculation a great deal less likely; negotiations were always anchored by two nation states rather than multiple ones. When small states were brought to the table, it was a nicety rather than a necessity.

And when the Soviet Union vanished, that left one policeman standing

The end of the Soviet Union meant the retreat of Russian power to within its own borders, creating a geopolitical vacuum that was a massive opportunity for American power. Essentially, Europe had one cop and swathes of ungoverned territory. The ungoverned bits stampeded for the protection of the single cop (or subsumed themselves in civil war, dictatorship or corruption) in order to ensure Russian power could not return.

This was a fantastic situation for most Europeans: for the first time in centuries Europeans were unlikely to die in a war. It took the burden of security off European nation states: from 1991 on, European states increasingly cut defense budgets, knowing that so long as they were under American-dominated NATO they were safe from conventional war.

In practice, this meant that any state that considered war as a means to an end had already lost. To go to war meant to risk upsetting the single cop who could bring to bear massive force to settle accounts. This is precisely what happened in the Balkans as Serb power was thwarted once the United States decided to impose a peace. While both the Croats and the Serbs committed their fair share of war crimes, the United States sided with the Croats since they were amenable to American influence and power while the Serbs were not. This intervention ended the Yugoslav Wars on secessionist terms rather than on Serbia’s.

Concurrently, the indigenous European Union expanded across the continent. This also served American interests, unifying a vast and diverse legal and economic realm underneath a single authority. Best of all, the EU had limited interest in developing a military force, relying instead on NATO as its security arm. It was a win-win: European citizens and elites got cheap security and a more-unified economic system while the Americans maintained their domination of a continent that, if unified, could well threaten the United States itself.

And a Europe mostly united by the EU and NATO was one where border changes became less threatening

In the old days of many cops, territorial changes of any kind immediately meant power was shifting. As much as was possible, European nation states tried to halt such changes. But a Europe with a single cop no longer had to worry about such balances of power. Power was wholly concentrated in the hard power of the United States and the soft power of the EU.

Which meant that once unfathomable political experiments could take place, knowing that the failure of such experiments held fewer risks. Most recently, Britain considered dissolving itself after having spent hundreds of years trying to forcefully unify the British Isles. That’s because a free Scotland wouldn’t have changed the island’s strategic balance: Scotland probably would have joined NATO as well as the EU, thereby being unavailable to threaten a rump Britain both militarily and economically.

This essentially goes for every nation state within the EU/NATO system: When you’re protected by the same army and play by the same rules, it doesn’t matter how big or small you are when it comes to security.

One of the amazing things about visiting Europe as a continent is its breathtaking cultural diversity: centuries of advanced civilization combined with the legacies of many wars and political systems have produced some fascinating enclaves. To pull together a nation within a nation is quite achievable for many of the bigger European states who, of course, were built through the conquest.

Prior to 1991, allowing such a process to follow its logical conclusion to independence and new nation states was beyond foolish: new states meant a new balance of power and under the bipolar and multipolar systems of yesteryear, few wanted to dare that. But the unipolar system of Europe means that such changes don’t matter so long as they don’t happen to the EU or the United States.

And Catalonia fits the bill of a nonthreatening secession movement

While Spain’s current constitution doesn’t currently allow secession (and few do), there aren’t many tools in Madrid’s toolkit to stop Catalonia should it decide to split. Spain can’t deploy tanks without risking its all-important EU and NATO memberships. Worse, the EU is likely to accept Catalonia as a new member; NATO, doubtless, would too, though even if it didn’t, a newly independent Catalonia would not, by itself, serve as a strategic threat to NATO’s domination of Western Europe.

Barcelona is seeking independence as part of a popular movement: culturally distinct Catalonians resent having much of their wealth transferred to Madrid while getting little in return. Madrid no longer provides security: NATO, dominated by the Americans, does. Nor does Madrid dictate much in regards to economic policy: that is more and more dominated by the EU. So what good does it do for elites in Barcelona to stay within Spain?

Which is why, despite opposition from distinct personalities, the secession process is going ahead

British prime minister David Cameron, American president Barack Obama and every elite in Madrid from the king on down are against Catalonian secession. But they all misread the geopolitical tea leaves. With the supranational structures of NATO and the EU in place, the borders of countries are minor details, little more than jurisdictions for police forces that are enforcing more or less the same laws. Just as you rarely notice when you move from one precinct to another, the same process is happening in Europe. Geopolitics favors secession: individuals complaining about the conditions don’t change the situation.

What could change that calculation? Well, any force that might threaten the EU/NATO system

Right now, Moscow is the most potent of threats to said structure. If the Russians looked like they were able to deploy power to a free Catalonia, the power politics would change and the niceties of the EU’s legal system would be forgotten in the rush to crush Catalonian independence. Someone would find an excuse, a law that would be technically broken. The conflict would morph from a legal dispute to a sanctions regime to, if it had to, unrest, civil war or outright invasion.

But the Russians haven’t the capability to take advantage of the situation and the Catalonians have shown no inclination to throw their hats into the sinking ship that is Vladimir Putin’s Russia. Catalonian independence isn’t part of a wider ideological movement that seeks to upend the international order but is simply using the tools already established since 1991 to allow small nations to carve themselves peacefully out of big states.

If Catalonian independence were being used by another big power to manipulate Europe, or if it were part of a revolutionary movement like the Islamic State seeking to change the entire international order, it would meet a much firmer, even violent, reaction. But it isn’t, which is why it won’t.

If Spain truly seeks to keep Catalonia, it will have to write an entirely new constitution that accepts Madrid needs Catalonia more than the other way around. That too is within the established rules of the system most of Europe lives under. But neither sanctions nor war are on the table.

The new Europe, same as the old Europe

So long as Catalonia joins both NATO and the EU, nothing fundamental changes about Europe. Madrid has a smaller tax base; Catalonia can provide more localized services; but Europe is just as stable as before with a single cop providing security and a single supranational institution tying together its many parts.

The map of Europe may get more complicated but its geopolitical situation will not. The United States will provide safety; the EU will work toward a common market. Catalonia on its own cannot threaten either. Catalonians should cheer; their independence is theirs if they want it.

This story first appeared at Geopolitics Made Super , November 10, 2015.