With the Basque Country and Catalonia going their different ways, the Spanish government has avoided the nightmare of a joint independence front between the two wealthy regions.
The northern Basque Country, home to 2.2 million people -- roughly one in four said to be a separatist -- wants to live in peace, taking advantage of the expected dissolution of separatist group ETA after decades of bloody attacks.
That contrasts sharply with Catalonia, where about half its 7.5 million people back independence and the region is now locked in a tense stand-off with Madrid.
"The interests today of the two regions are very different. One wants to protect what they have won; the others (Catalans) want more," said Pablo Simon, a political science professor at Carlos III University in Madrid.
- Shared history -
The two regions have felt close since the 19th century, when elite-led nationalist movements first appeared.
Both are industrial centres and they watched with a certain detachment as the rest of the country -- rural and largely illiterate -- collapsed into chaos after Spain lost its last colonies, notes Spanish historian Carlos Gil Andres.
General Francisco Franco's 1939-75 dictatorship was then a time of repression with the public use of their distinct languages banned.
But it was in the Basque region that the response was more radical.
ETA, set up in 1959, is blamed for the deaths of at least 829 people to 2010 in its campaign of bombings and shootings to achieve independence.
In Catalonia, nationalist group Terre Lliure set up in 1978 and which like ETA was Marxist, carried out only one killing. It disbanded in 1991.
- 'New coexistence' -
In 2003 Basque regional premier Juan Jose Ibarretxe proposed a status of "free association" with Spain.
He also wanted -- long before Catalonia -- a referendum on self-determination but the plan was rejected by parliament in Madrid.
Basque nationalist politicians however chose to respect democratic rules and avoid the confrontation with Madrid that Catalan leaders took on.
Today all sides in the region "want to build a new coexistence" and "avoid a repetition" of the years of violence, said Agus Hernan of the Forum Social, a group which is close to families of ETA prisoners.
The ruling conservative nationalist PNV party "realised that radicalisation would keep them from power," said Inaki Oyarzabal, a Basque senator with the conservative Popular Party.
- Unequal tax powers -
There is another key difference -- the Basque Country has since the 19th century had the power to collect its own taxes and decide for itself how to spend the money.
Basque leaders negotiate roughly every five years the "cupo", the amount they must give Madrid to pay for public services, said Simon.
They are therefore used to dealing with Madrid and are interested in maintaining the status quo.
This tax-and-spend advantage of the Basques fuels resentment in Catalonia.
The situation there has been made worse by "a perfect storm" driven by the drastic austerity measures adopted after the 2007-8 economic crisis and anger over corruption, said Borja Ventura who has written on both regions.
In 2011, the then head of the Catalan regional government, Artur Mas, was forced to enter the regional parliament by helicopter to avoid a crowd that had surrounded the building to protest austerity, Ventura recalled.
"And a way to bring people to his side was to mobilise them against an external enemy," he said, referring to the Spanish state.
- Civil disobedience -
Catalonia demanded the same "fiscal autonomy" but Madrid was unwilling to concede a region which accounts for 19 percent of Spanish economic output the same costly privileges enjoyed by the Basque Country which accounts for just six percent.
Over the following years, Catalan separatists repeatedly challenged Madrid?s authority and the decisions of the national courts until, on October 27, 2017, the parliament they controlled voted to break away from Spain after a banned independence referendum.
Oyarzabal, the Basque senator, said "there is no terrorism" in Catalonia but he likened the region's separatist drive to a "coup d'etat".
Catalans reject outright any suggestion their struggle can be compared to that of the Basques.
Joan Tarda, a lawmaker for Catalonia separatist party the Republican Left, said any comparison with the years of violence in the Basque Country "is an insult to intelligence and it trivialises terrorism".
"We opted for an enormous act of civil disobedience. But we will not deviate from our civic and peaceful method," he added.
ETA separatists address the press in 2011 when the Basque separatist group announced a permanent end to its campaign of violence which cost more than 800 lives
Thousands of people demonstrate against ETA in the town of Portugalete in 2002 after a bomb attack there
Catalans march in support of jailed pro-independence leaders and politicians in Barcelona earlier this month