MADRID — Tension is gripping Spain, with the national government and Catalonia’s political leaders clashing over the wealthy region’s push to secede.

Such a standoff has never happened before and is crucial for Spain’s future. “They are approaching a cliff … with consequences that are hard to predict right now,” says Joan Barcelo, a researcher on political conflicts at Washington University in St. Louis.

Here is a look at the latest developments in Spain’s worst political crisis in decades.

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WHAT DOES CATALONIA WANT?

The Catalan regional parliament in Barcelona passed a motion Friday unilaterally establishing a new country. The motion was approved by the votes of pro-independence lawmakers, with 70 out of 135 votes in favor of secession. The Catalan regional government supported the breakaway bid, though opposition lawmakers walked out of the chamber ahead of the vote in protest. Secessionists hold a slim majority in the current parliament.

Not all Catalans are keen on breaking away from Spain. Polls show they are roughly evenly split. The issue has been simmering for years and boiled over when a plan to grant Catalonia, with its population of 7.5 million people, greater powers of self-government was ruled illegal by the Constitutional Court.

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WHAT DOES THE SPANISH GOVERNMENT SAY?

The national government rejects Catalan independence, noting the constitution says Spain is “indivisible.”

The government deployed large numbers of police to Catalonia to stop an Oct. 1 regional independence referendum, which the Constitutional Court ruled illegal. Some heavy-handed policing caused outrage among Catalans.

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WHO WILL WIN?

After the Senate on Friday granted the government extraordinary powers to end the Catalan secession drive, the government dismissed the Catalan regional government, dissolved its parliament and called an early election for Dec. 21.

The pro-independence leaders and officials risk being arrested and sent to prison.

The central government’s measures will likely trigger a Catalan backlash. Resistance from public servants and regional police is probable, as are large street protests, which will keep the issue alive.

Regional elections in 2015 returned a slim majority of pro-independence lawmakers, who took this as a mandate to push ahead with the independence drive. Analysts predict a similar outcome in the upcoming ballot.