ON Sept. 11, hundreds of thousands of people took to the streets of Barcelona calling for Catalonia’s independence from Spain. Artur Mas, the Catalan prime minister, reacted by dissolving the regional Parliament and calling for elections on Nov. 25, which will likely strengthen his party’s position. Catalonia’s Parliament, which represents an autonomous region the size of Belgium in Spain’s northeast corner, has overwhelmingly supported holding a referendum on independence despite the Spanish Constitution’s ban on secession. So in addition to its economic woes, Spain now faces a deep constitutional crisis.

History can follow a capricious path, sometimes meandering slowly for decades only to accelerate abruptly and take a vertiginous turn. The immediate cause of Catalonia’s sudden outbreak of secessionist fever is so-called fiscal looting. The region accounts for about one-fourth of Spain’s exports. But for every euro Catalans pay in taxes, only 57 cents is spent in the region. Before taxes, Catalonia is the fourth richest of Spain’s 17 autonomous regions. After taxes, it drops to ninth — a form of forced redistribution unparalleled in contemporary Europe.

For a society suffering the acute pain of budget cuts and a deep recession, the burden of fiscal transfers, which cripple the Catalan economy’s ability to compete globally, is unacceptable. Unable to draw on its own tax base, the Catalan government recently went through the humiliation of being forced to ask Madrid for a bailout. Americans know well that an unfair taxation system can easily ignite calls for independence.

But money isn’t the only cause of secessionist sentiment. We Catalans have long been attached to our distinct identity and never accepted the loss of national sovereignty after being defeated by the Spanish monarchy in 1714. For three centuries, Catalonia has striven to regain its independence. Most attempts to establish a state were put down by force. The “Catalan question” was a major catalyst of the Spanish Civil War in the 1930s, and Gen. Francisco Franco’s dictatorship harshly repressed Catalan culture.