The gravest immediate threat to the West's long-term security does not emanate from Vladimir Putin or from the militants of the Islamic State. Rather, surprisingly, it comes from peace-loving Scots.
With polls now showing a majority of Scots supporting independence in the referendum set for Sept. 18, it's suddenly clear that Scotland might actually break away from Britain. In the words of Lord West of Spithead, former First Sea Lord, "A 'yes' vote for Scottish independence would make it more difficult to defend Britain. It would diminish NATO and the West's ability to do things."
Bluntly put, there is no rational upside for a 'yes' vote. In Scotland, the independence campaign runs on emotions alone. Abroad, its supporters are the postcolonial left who will revel in Britain's resultant weakness. Independence may increase Scotland's national pride, but its economy will suffer as companies and jobs flee south amid uncertainties about currency and taxation.
There will be no political dividend either. Unlike the "Irish problem" of the 20th century, the Scottish question is not a running sore in European or transatlantic politics. It does not involve a serious terrorist threat, nor would independence eliminate a destabilizing political movement — as would Corsican independence from France or Basque independence from Spain.
Simply put, Scottish independence is a solution in search of a problem. It would unwittingly destroy history's most successful political merger, the Anglo-Scottish Union of 1707, which enabled Britain to punch above its weight in the world, served as a model for the United States Constitution, and provided a dynamic core for a fiscal-military state that defeated its illiberal and undemocratic opponents in World War I, World War II and the Cold War.
Scottish independence would seriously weaken Britain as America's most important ally and as one of the key pillars of the Western world's security posture in the Middle East and Eastern Europe. An op-ed in the Guardian recently suggested that Britain without Scotland would be able to reduce its defense spending. But security is a positive-sum game. We are all safer when we work together and less safe when we compete or duplicate one another's efforts. In reality, a geographically reduced Britain will have to spend more to defend less favorable borders.
England's northern flank would be exposed for the first time in 300 years. All planning against possible Russian encroachments will have to be rethought. Both Scotland and what remains of Britain would henceforth become more reliant on the U.S. for their security and, therefore, less able to chart their own way in the world. Most vitally of all, the Scottish nationalists have announced that Britain's Trident nuclear deterrent, based on the west coast of Scotland, would have to be immediately moved, at an estimated cost of $8 billion. While Britain is struggling to recalibrate its defense posture amid such dislocations, Russia or the militant group Islamic State might seize the moment to further test Western resolve.
Scottish independence will inevitably cause headaches in continental Europe. It will open the floodgates for invigorated separatist demands from Catalonia and the Basques in Spain, the Northern League and South Tyroleans in Italy, and others. All this should be deeply worrying for the United States, which needs stable partners in London and Brussels capable of deterring Russian President Putin and (ideally) supporting the United States in other theaters as well.
Scottish nationalists naively seem to think global security will no longer be their concern. But leaving Britain will not mean that Scotland has changed neighborhoods. Scots may be able to opt out of foreign adventures in the Middle East, but since Russia's annexation of Crimea, Europe is once more a dangerous place. Will the newly independent Scots choose to move their country west toward Greenland? If not, who will protect Scottish natural resources against the kind of Russian encroachment that Norway routinely experiences?
There is thus a pervasive irony about Scots voluntarily breaking up a union designed in the 18th century to pool resources against foreign threats and thereby pitching themselves into a 21st century Europe that is at its peak of post-WWII instability. Independent Scotland might find it difficult to survive alone in such an environment. The only realistic "European" alternative would then be for Edinburgh to embrace the movement for deeper political, economic and military integration of the Eurozone. In that event, though, Scotland would own Europe's problems — the sovereign debt crises, immigration issues, the Russian threat and all. Moreover, its isolationist citizens would have to pay for profligate southerners. The supreme irony is that if the Scots vote for independence they may actually end up losing sovereignty over their own affairs.
Of course, neither Britain nor the world will go under if the Scots vote "yes" on Sept. 18. Even if copycat independence movements later detached Wales or Northern Ireland, England would always remain a power of enormous economic heft, military capability and cultural attraction. Still, England would be weakened by the destruction of the union — less able to act as a key U.S. ally and the main bridging power between the Atlantic and European systems. That would be a sorry day for all who value democracy, liberty, economic freedom and the cradle of liberal Western civilization.
Brendan Simms is a professor of history at Cambridge University, chairman of the Project for Democratic Union and author of "Europe: The Struggle for Supremacy, 1453 to the Present." Jason Pack is a researcher of world history at Cambridge University and president of Libya-Analysis.com.