MADRID (AP) — A high-stakes trial is bringing back a spotlight on the illegal kickback scheme that for years has haunted Spain’s Popular Party. The corruption cast a long shadow on the country’s main conservative party despite its pledges of regeneration. The proceedings at the National Court in Madrid are looking into whether the renovation of the party’s headquarters in the Spanish capital more than a decade ago was paid for with an alleged slush fund largely built on bribes. The case is the latest in a legal saga that began when allegations of the party’s decades-long shadowy accounting first emerged in 2013.