Catalans are due to vote on independence from Spain in a referendum next month, despite objections from Madrid.

Most of the arguments for independence are cultural or emotional. Opponents are more likely to point out concrete economic and security risks.

Arguments for

• Catalonia is a nation with its own culture and language.
• Spain has been unwilling to negotiate more autonomy. Independence is the only way to take (full) control of Catalan infrastructure, finances and policing.
• Catalonia pays more into Spain’s central government in taxes every year than it gets back in spending and subsidies.
• Catalonia has a dynamic and robust economy. It is responsible for more than half of Spain’s total startup investment. Eighteen million tourists visited the region last year, a quarter of Spain’s total. It has the second largest airport of Spain and the seventh busiest of Europe. Its seaport is the third largest of Spain and ninth largest in Europe.
• Outside Spain, Catalonia could write its own laws and regulations to accommodate its particular economic and social needs.

Arguments against

• Spanish- and foreign-born citizens make up between a third and half the population. They have no (strong) sense of Catalan nationhood.
• Independence would mean giving up and reapplying for EU membership. Catalonia would likely meet the technical criteria, but Spain could block its accession. (Unanimity is required from existing member states.)
• In the meantime, Catalonia would lose access to the European single market. Given its dependence on exports (it accounts for a quarter of Spain’s) and finance, that could be calamitous.
• An independent Catalonia would either need to mint its own currency or continue to use the euro informally like Kosovo and Montenegro — without the right to print currency and without a seat at the European Central Bank.
• An independent Catalonia would struggle to borrow given its poor credit rating.
• Catalonia’s economic dynamism owes much to expats and foreign companies, many of whom may relocate if growth stalls.
• Independence would mean leaving NATO and Madrid is unlikely to give an independent Catalonia “its” share of Spain’s armed forces.