Sunday's elections in Catalonia could put the wealthy northern region on a path toward independence, possibly triggering a constitutional crisis in austerity-weary Spain.
Some of the toughest budget cuts anywhere in the country have helped to exacerbate the traditional Catalan grievance that too much of the tax revenue they generate flows to poorer regions. Catalonia's government calculates it pays about €15 billion ($19 billion) more than it gets back from the national treasury every year. Regional leader Artur Mas has pledged to hold a referendum on independence if, as expected, he wins re-election.
But he can't do that on his own. Only the central government can authorize referendums, and Spanish Prime Minister Mariano Rajoy has said it won't do so in Catalonia. Mr. Mas's plans present a major headache for Mr. Rajoy at a time when he is preoccupied with stabilizing Spain's precarious financial situation.
The secession of Catalonia would spell failure for Spain's 30-year-old constitutional order, which sought to paper over Madrid's historic differences with Catalonia and the Basque Country, regions with their own languages and cultural identities, by giving them large amounts of political autonomy.
Some analysts believe that if Spain were to cede to Catalonia control over its own tax revenue and sharply reduce the amount it contributes to the Spanish treasury, that could help to defuse the crisis. But such an arrangement might be unconstitutional and would mean reduced financing for other regions at a time of deep economic crisis. In a stark example of hardship elsewhere, sanitation workers in the cash-strapped southern city of Jerez de la Frontera struck for 21 days this month in protest against planned budget cuts, leaving tons of garbage on the streets and leading to impromptu trash burnings by residents.
Nonetheless, the government can't afford to ignore the region's complaints after more than 1.5 million people thronged the streets of Barcelona on Sept. 11, Catalonia's National Day, to call for independence, the largest demonstration the regional capital had ever seen.
Likewise, Mr. Mas is in a tight spot. Beyond the legal obstacles to calling a referendum, a process of separation from Spain would be riddled with difficulties. Chief among these would be maintaining European Union membership, something EU officials have warned would be unlikely. But abandoning the effort could bring a popular backlash. A poll published recently by the Catalonia government's Center of Opinion Studies found 57% of the respondents would vote "yes" in a referendum on independence.
"We don't have a plan B," said Oriol Pujol, the No. 2 official in Mr. Mas's Democratic Convergence of Catalonia party.
Caught off guard by the massive Barcelona demonstration and rebuffed by Mr. Rajoy in his bid for a better financing deal, Mr. Mas has called elections two years ahead of schedule and is promising a referendum sometime during the next government's four-year term. The push for independence represents a shift for Mr. Mas's moderate nationalist party, which traditionally has sought to expand Catalonia's autonomy while remaining part of Spain.
Mr. Pujol, son of Jordi Pujol, a renowned Catalan politician who led the region's government for 24 years, said Catalan society had slowly become more pro-independence over the past decade as the Spanish government frustrated its attempts to gain more autonomy. He said the process had been accelerated by a fiscal crisis that has hit Catalonia especially hard because of a large debt load left by the previous, Socialist-led regional government and Catalonia's unfavorable financing regime.
Mr. Pujol said the new Catalan government would seek to open talks with Madrid on the referendum for independence. If Madrid refuses, it would try to find legal support for the poll in EU or international law.
Mr. Rajoy, on the other hand, has offered to open talks with the country's 17 regional governments on an overhaul of the country's regional financing scheme. Many in Catalonia, however, doubt that would lead to significant improvement for their region.
"It's easy to imagine that if the discussion is among all of the regions, all the others will be against the idea of Catalonia reducing the amount of funds" it transfers to the rest, said Josep González, head of Pimec, an association of small and medium-size businesses.
"Catalans are supporting spending cuts that are twice as deep as anybody else's…a wealth tax that just a few regions have, and a tourism tax that nobody else has," Mr. Pujol said.
The enthusiasm for independence has spread to many recent arrivals in Catalonia. At a rally for Mr. Mas targeted at the region's large immigrant community, Raúl Castro, a 49-year-old lawyer from Ecuador, said he supports the nationalist leader's program.
"It's a positive message, one of unity.…We are forming a new nation," said Mr. Castro. At the end of the rally, held at Barcelona's Contemporary Culture Center, the participants rose to their feet and sang "Els Segadors," the Catalan anthem.
Mr. Mas's party is aiming to capture a majority in Catalonia's highly fragmented 135-seat Parliament. The latest polls suggest he could fall short of that, though he would still receive the most votes by a wide margin. After the elections, Mr. Mas would be able to count on the support of smaller pro-independence parties to push forward with the referendum. The biggest of these is Republican Left of Catalonia, a party that has long advocated independence.
Leading the pushback against the independence tide is Alicia Sánchez-Camacho, head of Mr. Rajoy's conservative Popular Party in Catalonia.
"There is a temporary rise in nationalist sentiment for economic reasons, but it's not a deep-rooted structural change with an ideological basis," she said. With her "Catalonia, yes, but Spain too," campaign slogan and strategy of courting voters of all stripes who are frightened at the prospect of independence, Ms. Sanchez-Camacho could receive the second-highest number of votes, according to the polls.
Salvador Giner, head of the Institute of Catalan Studies, is skeptical that Catalonia can obtain independence, saying that it is an integral part of Europe and that its residents won't want to risk their EU membership. But he says Mr. Mas's challenge is an effective way to raise awareness of the region's complaints, obtain more autonomy and a better financing scheme.
After the elections, Mr. Giner said, "we will negotiate with the Spanish state.…Negotiate, that's what we've done for the last 1,000 years."