The amnesty was offered six years after a failed independence bid by Catalan separatists, with Sánchez insisting it would help “turn the page” on Spain’s worst political crisis in decades that still stirs up very raw emotions.

For years, Sánchez opposed such a move but recently admitted he’d had a change of heart.

Even though such a step was “complex to explain” to the Spanish public, it was a “necessary decision” to learn from what happened in 2017 and move towards a “resolution” of the conflict with Catalonia, he said Monday.

Promising the measure would be swiftly adopted by Spain’s parliament had won Sánchez the key support of Catalan separatist lawmakers that enabled him to be sworn in last month for a new term in office.

Once passed, the law will allow the courts to drop the charges against hundreds of separatist leaders and activists facing legal action over their role in the October 2017 crisis, in a process that should be completed within two months.

First and foremost, the move benefits Carles Puigdemont who headed Catalonia’s regional government when it staged a referendum banned by Madrid then made a short-lived declaration of independence.

Considered by many Spaniards as public enemy number one, he fled to Belgium to avoid prosecution although the amnesty will allow him to return home.

Absolute majority

Although the amnesty proposal is backed by a majority drawn from the ranks of the left, the radical left and Basque and Catalan parties, it has deeply divided Spanish society and provoked an outcry from parts of the judiciary.

In recent weeks, huge crowds of protesters have hit the streets in Spain to denounce the amnesty, answering a call by the right-wing opposition Popular Party (PP) placed first in July’s general election but without enough support to form a government.

“The amnesty is a form of political corruption because it is a means of getting into government in exchange for granting legal impunity,” said PP leader Alberto Núñez Feijóo on Monday.

The PP, which holds an absolute majority in the Senate, parliament’s upper house, has promised to do everything within its power to delay the adoption of the bill that the Socialists are pushing to have fast-tracked to speed up its promulgation.

The Senate can delay but not block the adoption of the measure.

Accusing Sánchez of a “coup d’etat”, the leader of the far-right Vox party Santiago Abascal went a step further in his criticism over the weekend, saying the prime minister would meet a dictator’s end.

“The time will come when… the Spanish people will want to string up (Sánchez) by the feet,” he told the Argentine daily Clarín, in remarks that prompted an angry backlash from the government.

READ MORE: Spain’s govt slams far-right leader who said PM will be ‘strung up by his feet’

Denouncing Abascal for “hate speech that seeks to polarise and incite violence”, Foreign Minister José Manuel Albares said such language hadn’t been heard “in Spain for many decades, since times that were very dark,” referring to the 1936-39 civil war and ensuing dictatorship that ended in 1975.

More worrying for the government is the fact that the amnesty has deeply divided Sánchez’s Socialists, with a survey published Monday in El Mundo daily showing 45.8 percent of those who voted for him in July were opposed to the measure.