Spain is a success story for democracy and development, and a net contributor to the global liberal order over the last four decades. One reason for this success has been Spain’s ability to maintain national unity for over five hundred years despite ethnic and linguistic diversity. A push for Catalan independence, however, calls that unity into question. A potential breakup of Spain by Catalonia is not in the U.S. interest, not in Europe’s interest, not in Spain’s interest and ultimately, not in Catalonia’s interest.

President Artur Mas, the Prime Minister of Catalonia, is visiting the U.S. this week to push an independence agenda. His efforts to split Catalonia from Spain should be more than a niche news story here in the United States. At a time when Europe is in significant political and financial turmoil, President Mas’ aspiration to create an independent Catalan state should be viewed with considerable skepticism.

President Artur Mas assumed office in 2010, and has pushed for Catalan independence since

The reality is that an independent Catalonia would face a messy divorce from Spain. Under any independence agreement Catalonia’s economy would take a serious hit—Catalans would have to assume a significant part of Spain’s debt. This challenge would be further complicated by the need to find a currency other than the Euro, as Spain would veto Catalan membership in the monetary union. For that reason alone, not to mention political uncertainty, there would be a likely exodus of multinational and Spanish companies to other regions in Spain. An independent Catalonia would have a hard time getting NATO membership for the same reasons.

Faced with a similar decision over national independence less than a year ago,55 percent of Scots voted against leaving the UK. In the lead up to the vote, President Obama came out against Scottish independence. It may be that the current leadership of Catalonia is using their current national debate to extract concessions from Madrid, but this is a dangerous game. Catalan leaders, including Mr. Mas, have failed to honestly present these costs to Catalan voters.

Spain was assembled through the merger, mainly by marriage, of smaller kingdoms with long and distinct histories; this is reflected in its national coat of arms. Several of these regions have longstanding cultural practices, dialects, and even languages. Catalonia is one such region— its language, Catalan, is a Romance language that shares both Iberian and Gallo-Itallic linguistic roots. Catalan is mainly spoken in Catalonia, the Balearic Islands, and an adjoining region in France. While most Spaniards have a sense of national identity, regional and local identities hold strong.

There has never been a Catalan kingdom, as Catalonia was part of the larger kingdom of Aragon, but Catalan as a language and as an identity has existed for hundreds of years. The notion of Catalan autonomy itself has a long history, but in spite of this longstanding idea of independence, Catalan political leaders have largely maintained a positive relationship with the national government—a position Mr. Mas shared up until a few years ago. The current Catalonian regional parliament consists of a mix of 3 nationalist parties and 3 non-nationalist parties. Under Mr. Mas’ more recent leadership, however, Catalonia has taken a sharp turn in public opinion towards independence.

One of the historic debates in Spain has been “what level of independence should various regions have?” After the Spanish Civil War, Franco’s answer was a total repression of the Catalan and Basque languages for ideological reasons, as well as to punish the Catalan and Basque nationalist forces who fought against Franco in the Civil War. Following Franco’s death, Spain held a constitutional referendum in 1978 as part of the transition to democracy under King Juan Carlos. Catalonia had strong voter turnout (67 percent) and even stronger support (91 percent) for the new Spanish Constitution. Among other things, the constitution righted the wrong of Franco era repression of Catalan and Basque languages by enshrining both cultural respect and high degrees of regional autonomy. As a result, Spain has five languages with official or co-official status: Castilian Spanish, Catalan, Basque, Aranese and Galician. Primary and Secondary Schools in Catalonia mandate that all subjects are taught in Catalan, with the exception of several hours each week set aside for Spanish learning.