Former Spanish Prime Minister Jose Luis Rodriguez Zapatero will begin two days of unprecedented court hearings on Wednesday (June 17, 2026) suspected of influence peddling, the latest corruption affair threatening the leftist government.

The investigation into the Socialist titan comes as a string of graft probes into Prime Minister Pedro Sanchez's family and former top political allies have threatened to topple his minority coalition.

Clashes with U.S. President Donald Trump and virulent criticism of Israel have made Mr. Sanchez a global progressive star, but the scandals have eroded the domestic standing of one of Europe's few remaining Socialist leaders.

Mr. Zapatero, who governed Spain from 2004 to 2011, was placed under formal investigation last month for alleged influence peddling in connection with the bailout of small airline Plus Ultra in 2021. Plus Ultra received 53 million euros ($61.5 million) of public money after the COVID-19 pandemic paralysed global travel.

Investigating judge Jose Luis Calama has said Mr. Zapatero allegedly headed a "stable and hierarchical" structure that used "opaque financial channels" to conceal the movement of money and obtain bribes for his illicit manoeuvring. Mr. Zapatero has denied the allegations, while Mr. Sanchez has expressed "full support" for his mentor.

A police search of Mr. Zapatero's office found jewellery and luxury watches valued at 1.3 million euros, leading Mr. Calama to probe additional alleged offences of tax fraud and smuggling. Mr. Zapatero's entourage attributes the hoard to a family inheritance.

Mr. Zapatero is due to speak at the Audiencia Nacional court in Madrid from 09 a.m. (0700 GMT) — becoming the first former or serving Spanish Prime Minister to declare as a suspect in a corruption probe.

"What is at stake is the reputation of someone who has become... the moral beacon of Pedro Sanchez and the current Socialist party," Astrid Barrio, a political science professor at the University of Valencia, told AFP.

Government under threat

Mr. Sanchez vowed to clean up Spanish politics upon taking power in 2018 after the main conservative Popular Party was convicted in its own graft affair. But a two-year-long investigation into his wife Begona Gomez for alleged influence peddling had already shaken the government, with a decision to send her to trial potentially coming in days.

Verdicts are also due in separate corruption trials of Mr. Sanchez's former right-hand man Jose Luis Abalos and his brother David Sanchez. Recent revelations about an ongoing police probe into a former Socialist activist suspected of leading a plot to sabotage investigations into Mr. Sanchez's entourage have piled further pressure on the government.

Amid the relentless stream of negative headlines, the Socialists have suffered four regional election drubbings since late 2025, in a possible precursor to next year's national vote. The conservative and far-right opposition have demanded Mr. Sanchez's resignation and early elections, saying the scandals have exposed systemic Socialist corruption.

Mr. Sanchez insists his government will see out its term until 2027. But researcher Barrio said "two very serious issues" could yet bring him down: being placed under investigation himself or a charge of illegal financing against the Socialists.