With former ministers and party heavyweights ​b​eing dragged into court, the country is once again confronting the unresolved legacy of political ​g​raft and ​shady backroom deals

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Easter will not have been a particularly celebratory time for Spain’s two biggest political parties. In a quirk of judicial fate, both the ruling Spanish Socialist Workers’ party (PSOE) and the conservative People’s party (PP) are bracing themselves after two high-profile trials involving former senior figures from each party began in Madrid this week.

Though vastly different, both cases have the potential to seriously dent each party’s claims of having zero-tolerance for corruption as voters in Andalucía, Spain’s most populous autonomous community, prepare for next month’s regional election. That will be followed by a general election next year.

So what are the cases? And why do they matter? The PSOE high command, including the prime minister, Pedro Sánchez, will be keeping a close eye on events at the supreme court, where the so-called “caso Koldo” – nicknamed after one of the defendants but also known as the “caso mascarillas” (masks case) – began yesterday morning.