Last year, Pedro Sánchez was unexpectedly re-elected to the leadership of his Socialist Party, seven months after being ousted in a party revolt and abandoning his parliamentary seat.
Last week’s verdicts in the corruption case made Mr. Rajoy’s party the first Spanish political force to be convicted of operating a slush fund and ordered to pay a fine, 245,000 euros, or about $285,000.
The party’s former treasurer, Luis Bárcenas, was sentenced to 33 years in prison and fined €44 million, alongside 28 other businessmen and politicians who received over 300 years in combined prison sentences for benefiting from a kickbacks-for-contracts scheme.
Mr. Rajoy and others from his party have acknowledged the damage since then, but they have also insisted that it did not imply that fraud was committed by Spain’s current administration or the party as a whole.
But Aitor Esteban, a Basque nationalist lawmaker, insisted on Thursday that the court ruling marked a “before and after” for Mr. Rajoy and his party.
He said that his own party was “not looking to destabilize Spain” but wanted to put an end to “months of political tsunamis,” caused by repeated corruption scandals and the “incapacity to reach agreements” of the bigger national parties, led by Mr. Rajoy’s conservatives.
Mr. Esteban congratulated Mr. Sánchez on making “a good move,” but also warned him to stay true to his pledge to resolve the crisis in Catalonia.
“I trust that the dialogue that you have promised will be real,” Mr. Esteban told Mr. Sánchez.
“You will face hostilities from day one,” Mr. Esteban added. “Your government will be very complicated, weak and difficult.”