Cassation, which considers the conformity of the petition to ordinary law, the reference for the Constitutional Court's judgment is the Constitution. If the Constitutional Court deems the referendum admissible, the President of the Republic has to set a date for the vote between April 15 and June 15. The final hurdle is that the result of the legislative referendum is only valid if at least a majority of all eligible voters go to the polling station and cast their ballot. If this quorum is not met, the referendum is invalid (which, in practice, means the law is not abolished). Electronic signatures The 2021 Italian budget law authorized for the collection of electronic signatures through a government run online platform, managed through the Italian online digital ID system SPID. Although the platform is not online, starting on July 1 2021 citizens have been able to add signatures to referendums through a provisional process. The new process has been noted for the speed at which it can collect signatures for referendums, with a referendum to decriminalize marijuana collecting 330,000 signatures in three days in due in large part to digital signatures. Political party use The political party in Italy that is most closely associated with, and has made most use of, referendums in the last 40 years is the Radical Party led by Marco Pannella. They hold the record for most referendums presented. Despite only receiving around 2.5% of the popular vote in most national elections, the numerous referendums they have proposed over the years have often mobilised the entire Italian political spectrum in support or opposition. They will often use unconventional methods such as prolonged hunger strikes and/or thirst strikes by their leaders to draw attention to their cause. Their largest political battles came in the 1970s and 80's when they successfully campaigned for the right to divorce and the right to abortion. Other groups have also made use of referendums to raise the profile of their own small political parties or their leaders or to raise awareness of their respective political agendas. Signatures for referendums have been collected by parties across the political spectrum from the Northern League opposing a law on immigration in 1998 (this was ruled as inadmissible by the constitutional court when presented), all the way to the Italy of Values party when leader Antonio Di Pietro collected signatures in 1998 for a change in the electoral