Pedro Nuno Santos poses for a portrait between the legislators of Socialist party and left bloc inside Portuguese parliament in Lisbon, Portugal June 21, 2016.
The resignation also left Costa's job as secretary-general of the Socialist Party (PS) up for grabs, and whoever wins the leadership race will run for prime minister.
Although Nuno Santos' popularity was hurt after he resigned in December 2022 in a scandal around a severance payout by state-owned airline TAP, he is seen as the front-runner by many.
Nuno Santos successfully coordinated support for a previous minority government with the far-left in 2015-2019.
Reporting by Catarina Demony and Sergio Goncalves; Editing by Andrei Khalip and Andrea RicciOur Standards: The Thomson Reuters Trust Principles.
Persons:
Pedro Nuno Santos, Rafael Marchante, Antonio Costa, illegalities, Marcelo Rebelo de Sousa, Jose Luis Carneiro, Carneiro, Nuno Santos, pollsters Aximage, Costa, Adelino Maltez, Costa's, Intercampus, Catarina Demony, Sergio Goncalves, Andrei Khalip, Andrea Ricci
Organizations:
Socialist, REUTERS, Rights, Socialist Party, Interior, TAP, Diario, Socialists, Social Democrats, Thomson
Locations:
Lisbon, Portugal, Rights LISBON, Portuguese