The European Union has brought 28 countries into a closer political and economic union. Paradoxically it has also made it more feasible to contemplate the breakup of some of those countries.

Independence for a small state outside of a political and economic group like the EU would be risky nowadays. Within the EU, however, the barriers between states — and thus the economic and political risks of independence — are lower.

Consider Scotland, where a popular referendum on independence will be held on Sept. 18. The referendum is the result of the landslide victory by the Scottish National Party in the 2011 Scottish Parliament election.