A man shouts slogans during a regional strike called by pro-independence parties and unions in Barcelona, Spain on October 3, 2017.Susana Vera / Reuters

Thousands of people filled the streets of Spain’s northeastern region of Catalonia Tuesday to protest the violent police crackdown on the autonomous region’s contested independence referendum, which left more than 800 people injured. Called by pro-independence groups and Catalan trade unions, the strike is occurring as the Catalan government’s anticipated declaration of independence—and Madrid’s response—threatens to push the country into the most serious constitutional crisis in its 40-year democratic history.

Sunday’s referendum, which saw a turnout rate 10 points higher than a similar vote held in 2014, resulted in an overwhelming 90 percent vote in favor of Catalan independence—though turnout was still only around 42 percent of eligible voters. The results prompted Carles Puigdemont, Catalonia’s regional president, to declare that the region’s citizens had “won the right to an independent state in the form of a republic.” He added that the regional parliament would decide its next steps, signaling that a formal declaration of independence may be imminent (the Catalan government committed to issuing a unilateral declaration of independence within 48 hours of a “Yes” majority vote).

Though Puigdemont said Monday that he isn’t seeking “a traumatic break” from Spain, the national government could make it that way if any break comes to pass. Madrid has so far refused to recognize the vote’s validity, reiterating its stance that the referendum was unconstitutional and therefore lacking in legal force. It’s a position external observers appear to share. Despite global condemnation of the violent tactics the national police used to shut down the vote, Catalonia’s independence bid has failed to get the backing of any country or major international body. The European Union has stood firmly behind the Spanish government throughout the crisis, which it says it is treating as an “internal matter” of Spain, though the European Parliament is scheduled to convene Wednesday to debate the issue.

Katy Collin, a post-doctoral fellow at the Brookings Foreign Policy program, told me that while similar votes, such as last week’s Kurdish referendum, have backing from some international actors, the goal of Catalonia’s vote made it more difficult to support. “As unlikely as it as that Catalonia could get concessions from Madrid that it’s looking for—or that it did look for in 2012 and 2010 and 2006—it’s better to negotiate, which is what the Kurds are doing in Iraq,” she said, noting that the Kurdish strategy was focused on bringing Baghdad to the negotiating table rather than unilaterally declaring independence. “But the Catalans have said the opposite, that ‘We tried to negotiate and got shut down and now we’re going to declare our independence.’”

On a legal level, any such declaration would be symbolic. Carlos Flores Juberías, a professor of Constitutional Law at the University of Valencia, told me Catalonia lacks the means to enforce a unilateral declaration, let alone the ability to draw its own borders. “The Catalan government does not have the possibility to effectively run the territory as an independent state—they cannot control the airports, they cannot control the highways, they cannot control the budget, and so on,” he said. And it’s unlikely Madrid would even let them try. Instead, the Spanish government is widely expected to take the unprecedented route of invoking Article 155 of the Spanish constitution, which permits the national government to take the “measures necessary” to regain control of an autonomous region in the event that “it does not fulfill the obligations imposed upon it by the Constitution or other laws, or acts in a way seriously prejudicing the general interests of Spain.”

Still, a Catalan independence declaration, and a refusal by Madrid to acknowledge it, would certainly have repercussions. In addition to protests that have already begun throughout the region, a move by Madrid to suspend Catalonia’s self-government could involve the deployment of additional military police or the replacement of regional leaders. And the fact that Article 155 has never before been invoked means it’s not clear what “measures” the government should be expected to take—nor how the Catalans would respond to them.

“It’s a constitutional crisis,” Collin said. “That they’re going to potentially strip the regional government of its authority and govern Catalonia from Madrid. … I don’t see it going in the direction of conflict resolution.”

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