Catalonia may be the catalyst for a renewed wave of separatism in the European Union, with Scotland and Flanders not far behind. The great paradox of the European Union, which is built on the concept of shared sovereignty, is that it lowers the stakes for regions to push for independence.

While a post-national European Union may be emerging out of the euro zone crisis, with a drive for more fiscal union and more centralized control over national budgets and banks, the crisis has accelerated calls for independence from member countries’ richer regions, angry at having to finance poorer neighbors.

Artur Mas, the Catalan president, recently shook Spain and the markets with a call for early regional elections and promised a referendum on independence from Spain, although Madrid considers it illegal. Scotland is planning an independence referendum for the autumn of 2014. The Flemish in Flanders have achieved nearly total autonomy, both administrative and linguistic, but still resent what they consider to be the holdover hegemony of the French-speakers of Wallonia and the Brussels elite, emotions that will be on display in provincial and communal elections Oct. 14.

There are countless things that hold unhappy countries, like marriages, together — shared history, shared wars, shared children, shared enemies. But the economic crisis in the European Union is also highlighting old grievances.

Many in Catalonia and Flanders, for example, argue that they pay significantly more into the national treasury than they receive, even as national governments cut public services. In this sense, the regional argument is the euro zone argument writ small, as richer northern countries like Germany, Finland and Austria complain that their comparative wealth and success are being drained to keep countries like Greece, Portugal and Spain afloat.

The crisis has also produced a loss of confidence in traditional leadership, with voters punishing incumbents and mainstream political parties. That has helped more atavistic nationalist parties, like the National Front in France and Golden Dawn in Greece. But in separatist regions, the same disaffection tends to favor parties advocating independence.