BARCELONA — With three weeks to go until a referendum called to dissolve a 500-year-old political union, neither the Spanish nor the Catalan governments are confronting head-on arguments about why Catalonia should secede from or remain in Spain.

Instead, they are focusing on whether the Catalans have the legal right to secede.

But that's not the case in Barcelona, with many of those who took to the streets on Monday for the Diada, Catalonia’s national day, happy to talk about specific grievances that have pushed them toward independence. Organizers said 450,000 people had registered to take part in the Diada, and Barcelona police later tweeted that 1 million turned up.

Catalan President Carles Puigdemont, backed by a separatist majority in the regional assembly, has vowed to go ahead with the vote on October 1, which has been ruled illegal by Spain’s Constitutional Court. However, Puigdemont and his Cabinet aren't (publicly at least) shouting about a future, independent Catalan state, rather focusing their campaign on allowing citizens to decide their own future, not being dictated to by Madrid.

Catalonia has 16 percent of the country’s population and generates 20 percent of its gross domestic product.

The Spanish government, meanwhile, is sticking to the legal arguments, with Prime Minister Mariano Rajoy saying he will do “whatever is needed" to prevent the vote taking place.

Spain faces one of its gravest political crises in decades. Many in the establishment wonder if the situation could lead to unrest in the streets and ask how Rajoy will be able to prevent the vote without using drastic measures — such as taking control of the regional government.

“I want a fair country, a more social and leftist country, and I believe the best way to achieve that is leaving Spain,” said Marc Becat, a 22-year-old who works in sales. “Spain has always looked to me … pretty conservative, not only at the political level but also in terms of thinking.”

A number of legal obstacles stand in the way of Becat's wish coming true.

Judges are investigating Puigdemont and other officials on charges related to the organization of the referendum that may result in prison sentences. The public prosecutor has ordered the police to monitor activities connected to the vote — a print shop and a newsroom have been raided in the past few days, triggering public demonstrations. Hundreds of mayors in Catalonia have defied court orders and offered their support for the vote, although others, especially in the bigger cities, have refused to do so.

It's the economy, stupid

Against this background of tension, however, there is little political debate about the reasons that led a significant number of Catalans — around 41 percent, according to the Catalan government-funded Centre d’Estudis d’Opinió (CEO) — to be willing to break away from Spain.

Research by the CEO shows the reasons to be manifold, with arguments including wanting increased autonomy (26 percent), the belief that Catalonia would improve if it struck out on its own (23 percent) and the desire for a new model for running a country (19 percent).

Catalan unionist forces, as well as the Spanish government, accuse the separatists of feeding the people with lies and a constant stream of distorted facts aimed at reinforcing a Catalan sense of victimization at the hands of Spaniards. They haven’t been able to fully combat those perceptions, real or imaginary, on the ground.

Towering above all else is the economy. Catalonia has 16 percent of the country’s population and generates 20 percent of its gross domestic product.

“All the money and all the taxes that flow to the Spanish government will stay in [an independent] Catalonia,” said Ana Martí Benavente, a 78-year-old Barcelona pensioner. “It’s like a son who wants to leave home but is the one bringing in the money. And of course the parents don’t want him to leave.”

“With the work in the industrial areas, the exports and the Catalans’ personality, we could build a country where people would live better than in Switzerland in some years,” said Gabriel Maestro, a 74-year-old engineer.

Other separatists point to cultural differences and perceived aggression from the central government.

“We believe we are different in Catalonia and we have rights that are being walked over,” said Mari Angels Cubillo, a 47-year-old housewife.

“Most families with Catalan roots have never felt Spanish,” added Roser Brustenga, a 62-year-old office worker, arguing that an independent Catalonia would preserve its own language and culture, which “the current government is trying to eliminate.”

“What we Catalans find surprising is how the international community doesn’t react to the fact that we’re being prevented from voting” — Marta Alsina, teacher

Language comes up again and again out on the streets. Most people in Catalonia can speak Catalan and Spanish, both official languages. Catalan is the main language in schools, but in recent years, courts have been telling Catalan schools to provide lessons in Spanish if students demand it. Secessionist supporters see that as an attack on a language in need of protection.

Many supporters of an independent Catalan state can even refer to specific quotes from Spanish officials that have offended them.

Marc Becat recalled the words of former Education Minister José Ignacio Wert, who in 2012 said his aim was to “españolizar [make more Spanish] Catalan children.”

Brustenga remembered a leaked conversation from 2016, in which an official in the anti-fraud bureau boasted to a Spanish minister that they had “destroyed [the Catalan] health system.”

Others are angry about the conservative government of Rajoy’s Popular Party.

“It’s the Popular Party above all things, I hate them, that’s it,” said Alex Fores, a 21-year-old engineering student. “They’re very right-wing and obviously if you look at what people vote here [in Catalonia] it’s a completely different ideology.” Catalonia is ruled by a pro-independence coalition led by one center-right party and one center-left one.

While many demonstrators on Monday seemed convinced that they will be able to cast a vote on October 1, they were aware that it hangs in the balance.

“What we Catalans find surprising is how the international community doesn’t react to the fact that we’re being prevented from voting,” said Marta Alsina, a 46-year-old teacher.

“I’m hopeful that things will change from October 2, even if the referendum doesn’t take place,” said Josep Maria Alventosa, a 70-year-old architect.