The Italian electoral law of 2015, better known as Italicum,[17] a name given to it in 2014 by the Democratic Party secretary and subsequently head of government Matteo Renzi, who was its main proponent (until the end of January 2015 with the support of Forza Italia's leader Silvio Berlusconi) provides for a two-round system based on party-list proportional representation (the former being ruled out as unconstitutional),[18] corrected by a majority bonus and a 3% election threshold. Candidates run for election in 100 multi-member constituencies with open lists, except for a single candidate chosen by each party who is the first to be elected.