Commissioned by Silvio Berlusconi, who on 4 October 2005 "threatened the government crisis in the event that proportional electoral reform was not approved", the law was approved a few months before the general election with the votes of the House of Freedoms, without the consent of the opposition, that criticized and opposed it. In 2009, three abrogative referendums were held, aimed at changing this law in several places. These referendums, initially set for 18 May 2008, were then postponed to 21 June 2009 due to the early dissolution of the Houses, which took place on 6 February 2008. None of the three referendums reached the quorum of the majority of those entitled. On 17 May 2013, the Supreme Court of Cassation harshly criticized the Calderoli law, highlighting important questions of constitutional legitimacy and entrusting the Constitutional Court with a possible judgment of unconstitutionality. On 4 December 2013 the law was declared unconstitutional by the Constitutional Court in reference to the majority prize awarded to the most voted coalition, without a minimum threshold to be reached in order for the prize to be taken, and the impossibility for the voter to provide a preference.
Main characteristics
Proportional system and blocked lists
The law introduced a system based on the proportional electoral formula of the "whole quotient and the highest remnants", but with a substantially majority spirit due to the thresholds and the strong majority premium. It provided for a system of blocked lists, in which the voter could not express any preference vote.
Majority prize
It also provided for a majority prize, to be awarded nationally for the Chamber of Deputies, and in each region for the Senate of the Republic. For the Chamber, it was established that to the list or coalition that obtained the majority of the votes but did not obtain the 340 seats, was assigned a further quota of seats beyond those already obtained, in order to reach this number. The 12 seats assigned to the Italians abroad constituency and the seat assigned to the Aosta Valley were assigned according to different rules: the relative votes were not calculated for the determination of the list or coalition of lists of relative majority and therefore did not contribute to triggering the majority premium. For the Senate, it was established that the list or coalition that obtained the majority of votes in the Region but did not receive 55% of the seats assigned to it, were assigned a further quota of seats, in order to reach that number.
Explicit programs and alliances
The law provided for the obligation, together with the presentation of electoral symbols, for each political force to deposit its program and to indicate its head. It also envisaged the possibility of mutual recognition between multiple lists, grouped together in coalitions.
Thresholds
To get seats in the Chamber, each party or list had to get at least 4% of the national votes while the coalitions had to get at least 10%. The lists linked to a coalition that exceeded the prescribed threshold participated in the allocation of seats if they exceeded 2% of the votes; the first party below this threshold within the same coalition also participated in the allocation of the seats. To obtain seats in the Senate, each party or list had to get at least 8% of the votes while the coalitions had to get at least 20%. The lists linked to a coalition that had exceeded the prescribed threshold, participated in the allocation of seats if they exceeded 3% of the votes. To protect the recognized linguistic minorities it was envisaged that the lists representing them, whether coalitioned or not, could still have access to the allocation of seats for the Chamber of Deputies obtaining at least 20% of the votes in the constituency in which they compete. For the Senate of the Republic, it was envisaged that 6 of the 7 seats due to Trentino-Alto Adige be assigned through uninominal colleges, maintaining in this single Region the mechanism envisaged by the previous election law.
