BARCELONA, SPAIN - SEPTEMBER 28:  Students get caught in an air vent as they gather to demonstrate against the position of the Spanish government to ban the self-determination referendum of Catalonia during a strike by university students on September 28, 2017 in Barcelona, Spain. The Catalan government is keeping with its plan to hold a referendum, due to take place on October 1, which has been deemed illegal by the Spanish government in Madrid.  (Photo by Dan Kitwood/Getty Images)
Catalonia: What you need to know
01:10 - Source: CNN
CNN  — 

Catalonia’s separatist government is adamant it will go ahead with a referendum on October 1 to decide if the region should split from Spain, despite the country’s highest court banning the vote.

Spain’s Constitutional Court has outlawed the plebiscite, and the national administration in Madrid asserts that any such vote would be unconstitutional.

The dispute between the regional government in Barcelona and the Spanish government has become increasingly bitter in recent weeks, with several high-ranking Catalan officials involved in organizing the referendum arrested, and mass protests in the region’s capital of Barcelona and other towns.

On Tuesday, US President Donald Trump weighed in on the debate, casting doubt on recent polling suggesting a “Yes” vote will win and saying that he is for “a united Spain.”

“I really think the people of Catalonia would stay with Spain. I think it would be foolish not to.”

The vote risks plunging the country into one of its worst political crises since the end of Gen. Francisco Franco’s dictatorship four decades ago.

Hundreds of thousands have attended rallies to demand their region break from Spain in recent weeks.

The basics…

Catalonia is a wealthy region in Spain’s northeast. One of 17 autonomous provinces, it has its own regional government – or Generalitat – which already has considerable powers over healthcare, education and tax collection.

But it pays tax to Madrid, and pro-independence politicians argue that complex mechanisms for redistributing tax revenue are unfair on wealthier areas. 

Catalonia has long complained that its revenues subsidize other parts of Spain. The region hosts some 16% of the Spanish population and much of the country’s manufacturing and finance sectors.

Catalan nationalists argue that they are a separate nation with their own history, culture and language and that they should have increased fiscal independence.

A banner reading "I just want to vote" is seen as demonstrators gather outside the Catalan high court.

How did we get here?

The long-running dispute goes back to the brutal years under Franco, whose dictatorial regime repressed Catalonia’s earlier limited autonomy. It wasn’t until four years after his death in 1979 that the region gained full autonomy.

In 2006, the Spanish government backed Catalonia’s calls for greater powers granting “nation” status and financial control to the region.

But it was one step forward and two steps back four years later, when that status was rescinded by the Constitutional Court, which ruled that while Catalan is a “nationality,” Catalonia is not a nation itself.

Separatist supporters demonstrate in front of the Catalan high court building on Thursday in Barcelona.

Catalonia’s campaign to break away has been gaining momentum since 2010, when Spain’s economy plunged during the financial crisis. It was further galvanized by the Scottish referendum for independence in 2014, which ultimately saw voters opt to remain part of the United Kingdom.

Catalonia held a symbolic poll in 2014, in which 80% of voters backed complete secession – but only 32% of the electorate turned out.

What’s behind this latest drive?

Catalan leader Carles Puigdemont has fought to establish an independent Catalan state since taking office last January, and called the referendum in June.

A month later, the Generalitat approved a law allowing it to formalize plans for the October plebiscite.

But it would appear support for an autonomous Catalan state has fallen in recent months, according to a June poll conducted on behalf of the regional government. The survey indicated some 41.1% were for independence, down from 44.3% in March.

Where does Madrid stand?

Firmly against Catalan independence, the central government has vowed to shut down what it says is an “illegal” referendum. It has the authority to do this, under Article 155 of the Spanish constitution.

Spain's PM has called on separatists to stop the "escalation of radicalism and disobedience."

Madrid asked the Constitutional Court to suspend Catalonia’s referendum law, which had paved the way for the ballot. Spain’s high court is now investigating whether the regional government has breached the constitution.