MADRID--Spain's government on Friday said it would petition the constitutional court to block a symbolic vote on independence in Catalonia, the second time in recent weeks that it has sued to halt a ballot on the wealthy region's status.

Deputy Prime Minister Soraya Sáenz de Santamaría said the Catalan plan for the Nov. 9 vote, with volunteer poll watchers and same-day voter registration, represents a "legal fraud" and "a perversion" of the democratic process.

It was expected the court would grant the government's request for an injunction, as it did in September, when justices blocked a previous Catalan government plan to hold a nonbinding referendum. But analysts said another legal victory for Prime Minister Mariano Rajoy's government wouldn't resolve the political discontent simmering in Spain's leading industrial region, which is increasingly at odds with the rest of Spain over economic and linguistic issues.

In a news conference Friday afternoon, Catalan leader Artur Mas vowed to put forth a vigorous legal defense of the vote, which he has dubbed a "citizen participation process." He said: "I thought one of the principles of democracy is listening to people and allowing them to give their opinions. If people can't express their opinions, then it's not a democracy of great quality." He said the central government was being hypocritical by putting obstacles in the path of Catalan voting plans, and then criticizing the alternative voting measures the region was subsequently forced to adopt.

Even before Friday's announcement of a legal action, pro-independence citizens groups in Barcelona were anticipating Madrid's move and calling for Catalans to rally in front of polling places on Nov. 9. Catalonia has witnessed massive street demonstrations in recent years, with hundreds of thousands of pro-independence demonstrators forming a miles-long "V" for vote, in September.

Mr. Mas canceled the original referendum on Oct. 14 after the court injunction following the first lawsuit by Mr. Rajoy's government. On Friday, Ms. Sáenz de Santamaría said that Catalonia's substitute voting plan amounted to an effort to circumvent the earlier court decision by concealing the government's organizing role. "The person organizing [the vote] doesn't want to assume any responsibility or sign anything," she said.

She also accused Mr. Mas of placing thousands of volunteers in a legally dubious position, noting that teachers were being pressed to open schools to serve as polling places. "We intend to guarantee the rights of the Catalans and especially public servants, whom the local government would leave legally exposed," Ms. Sáenz de Santamaría said.

It seemed likely that Mr. Rajoy's government would win the legal battle and that Catalan activists would hold some kind of protest event Nov. 9, said Emilio Sáenz-Francés, a professor of history and international relations at Comillas Pontifical University in Madrid. "The key question is what happens Nov. 10?" he said. "Enforcing the law is one thing, but how does the government resolve the divorce between Catalonia and the rest of Spanish society?" He said it is hard to be optimistic that a solution is close.

A poll released Friday by the Catalan government's Center for Opinion Studies indicated that pro-independence sentiment remains robust in Catalonia. It showed that 49.4% of Catalans would vote "yes" to both questions on the proposed Nov. 9 independence ballot. The first question is should Catalonia be a state. The second is should it be an independent state. The poll found that 19.7% would vote "no" to both questions, and 12.6% "yes" to the first question and "no" to the second.

Catalan separatists complain that Madrid drains the region of taxes without respecting its language or culture. The Madrid government says it has offered Catalonia plenty of economic assistance and that Catalonia enjoys ample autonomy under Spain's constitution.

Write to Matt Moffett at matthew.moffett@wsj.com

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