There have long been fears that a successful secessionist effort will encourage other potential secessionists, potentially causing a domino effect. These fears are over-wrought. The reality is that each secessionist movement is driven by domestic dynamics, and the examples set elsewhere are almost entirely irrelevant. Whatever happens in Scotland next year will only matter in Scotland and in the rest of the United Kingdom. Whether the vote is for or against independence, it will not matter much to the rest of the world.
Why? For two reasons: there are always multiple lessons to be learned, so people tend to learn the lessons they want; and nearly all politics is local. We also have some scholarship that suggests that separatism is “contagious” under very limited circumstances. Let me explain.
In the aftermath of the nearly simultaneous disintegrations of Yugoslavia, the Soviet Union and Czechoslovakia, there was some thought that separatism was akin to a contagious disease spreading across Europe. The problem is that each “domino” presented both positive and negative lessons to those thinking about separatism elsewhere. When Yugoslavia broke apart, it could have encouraged potential secessionist movements or discouraged them, depending on whether such groups viewed themselves as being akin to Slovenia or to Bosnia. When the Soviet Union disintegrated, it could have prompted more separatism if those elsewhere viewed themselves as being in a similar situation as Estonia, but perhaps not so much if they felt more similar to Azerbaijan.
The political psychological dynamic at play here is confirmation bias. Reality will produce all kinds of things to observe, and people will tend to observe those dynamics and those lessons that reinforce their existing attitudes. Americans, for instance, are still arguing over the lessons to learn from Vietnam, with some arguing that the US used too little force and others arguing it used too much.
A more direct comparison and more recent example is the discourse that developed in Canada in the aftermath of Montenegro’s referendum in 2006. Quebec separatists were impressed at the ability of Montenegro to hold a referendum and then become independent once the threshold was exceeded, without prolonged bargaining with the rump state—a unilateral declaration of independence. Canadian federalists, on the other hand, noticed that the threshold was set at 55% rather than the 50% + one that had been the standard in past Quebec referendums.
The first key point here is this: whatever the outcome in Scotland is, it will be read by those elsewhere in ways that confirm their attitudes. If Scotland does not become independence, motivated secessionists will indicate how Scotland is not a relevant or comparable case. If Scotland does become independent, then those opposing secession elsewhere will argue Scotland is a special case that does not a set a precedent.
The second point is that secessionism is largely driven by domestic politics. Whatever happens in Scotland, potential separatists in other countries will be motivated by more immediate concerns: can their group gain access to power via elections? Is power decentralized? Is their group oppressed? Can separatism be used to outflank other parties? The apparent spread of secessionism in Eastern Europe and the Soviet Union in the late 1980s was not because one outbreak causing others, but that the advent of political competition provided politicians running for office in sub-state units—the various Soviet Socialist Republics, Slovenia, Croatia and the others—with incentives to play towards narrower audiences. The first elections were at the sub-national level, which meant that more homogeneous audiences were the electorates that mattered, leading to a focus on ethnic nationalist concerns.
The separatists beyond Scotland will have more or less support and will be more or less motivated not by the outcome in Scotland but by the people they seek to mobilize and represent. The local conditions matter the most. The only place where Scotland’s independence could affect the interests of potential separatists is the United Kingdom. What would the departure of Scotland mean for the balance of power within the UK? This is far less clear than the departure of Slovenia and Croatia from Yugoslavia. Will Wales feel at greater risk of tyranny of the majority from the English in a Scotland-less United Kingdom?
To be clear, there is one mechanism that causes secession in one spot to reverberate elsewhere, but it is absent in this case. Studies have shown that when a group is separatist in more than one country, the activity and the outcomes in one country may matter in other places that group resides. For instance, when Kosovo became independent (de facto in 1999), that had ramifications for other places where Albanians resides—especially Macedonia. If the Kurds in Iraq become independent, that will have implications for the Kurds in Turkey, Syria and elsewhere. However, there are no similar groups of Scots in other countries that might become more separatist in the aftermath of a successful referendum.
In sum, while the referendum will be quite important for Scotland and for the United Kingdom, it will have a minimal impact beyond. Worries about precedents are exaggerated as local politics triumphs over the ebbs and flows of secessionism elsewhere. So, the Scots should vote based on what it means for Scotland, and outsiders should be concerned only insofar as independence would affect their interests in Scotland.