Majority jackpot system
The majority 'jackpot system, also known as a majority-minority apportionment, is a and conditional voting rule.' It produces semi-proportional representation by fixing the final apportionment for a party or alliance that wins a majority or plurality of the vote at some level. It differs from the similar majority bonus system in that the total number of seats received by the winner is fixed, whereas the bonus system assigns a fixed number of "bonus" seats to the winning party.
It is currently used in Armenia and San Marino, and was previously used in Italy from 2006 to 2013.
An example of a very small, almost insignificant majority jackpot type correction system is found in Germany's electoral system for the Bundestag. If a party receives more than half of the list votes, but does not receive more than half of total seats, they receive as many seats as necessary, which are added to the size of the Bundestag.
History
was the first politician to enact a law to give automatic seats to the winning party and ensured his victory in the 1924 Italian general election. The system was reintroduced for the 1953 Italian general election, in which any parliamentary coalition winning an absolute majority of votes would be awarded two-thirds of the seats in Parliament. The Christian Democracy-led coalition fell narrowly short of this majority in the election, and the system was abolished before the 1958 election.The electoral system for Hungary used in 1949 had a national majority jackpot/bonus, whereas a list of a party or alliance receiving at least 60% of the vote nationally would be entitled to 80% of seats allocated on a national level, and a list over 80% would be entitled to 100% of seats allocated on a national level.
A plurality jackpot system which awarded 55% of seats to the largest party was introduced in Italy for local elections in 1993 and national ones in 2006. In the 2013 Italian general election, the Democratic Party won 292 seats in the House using its 8,644,523 votes and so needed 29,604 preferences to obtain a seat. Its major opponent, The People of Freedom, won 97 seats with 7,332,972 votes and so needed 75,597 votes for a single seat. The system in use in Italy from 2006 until 2013, which assigned the jackpot to the plurality party, was judged unconstitutional by the Constitutional Court of Italy. After a proposed modification involving a run-off vote was also struck down, a variant of parallel voting was adopted for the 2018 Italian general election.
Jackpot vs. bonus
The jackpot system ensures the winning party or alliance ends up with at least a certain fixed number of seats in total, by granting it however many additional seats are needed. In the Sanmarinese Parliament, the majority alliance is given 35 out of 60 seats. A majority jackpot system can be seen as a variant on the additional member system, where a set of seats are assigned by the plurality principle, while the rest of the seats are assigned with the proportionality principle, taking into account the seats already distributed. This means if the majority jackpot is set at 55%, and the largest party/coalition receives 35% of the vote, they will be entitled to the additional 20% to reach 55%, but no more. The rest of the seats are distributed among the other parties, unlike the majority bonus system, which would not take them into account. If the largest party would receive 60% of the vote, they would be entitled to the additional 5% of seats above the majority jackpot, unless there is also a minority jackpot. The size of a jackpot is typically above 50%, to provide for a clear majority, but may also provide for a certain size of supermajority.| Size of jackpot | Vote share of the largest party | Vote share of the 2nd largest party | Appr. seat share of the largest party | Appr. seat share of the 2nd largest party | Effective bonus for largest party | Effective bonus for second-largest party |
| 50% | 35% | 25% | 50% | 19% | 15% | -6% |
| 55% | 35% | 25% | 55% | 17% | 20% | -8% |
| 60% | 35% | 25% | 60% | 15% | 25% | -10% |
| 50% | 45% | 25% | 50% | 23% | 5% | -2% |
| 55% | 45% | 25% | 55% | 20% | 10% | -5% |
| 60% | 45% | 25% | 60% | 18% | 15% | -7% |
| 50% | 55% | 25% | 55% | 25% | 0% | 0% |
| 55% | 55% | 25% | 55% | 25% | 0% | 0% |
| 60% | 55% | 25% | 60% | 22% | 5% | -3% |
The table below shows the difference between the jackpot and bonus rules.
The jackpot system essentially gives the size of the jackpot or the vote share, while the bonus system gives a fixed bonus and a proportional share of the rest of the seats. The jackpot only modifies the seat share when the largest party's proportional seats count based on its vote share is below the size of the jackpot. A jackpot system may also have further conditional elements: it may provide for a supermajority jackpot only for a party which received an absolute majority of vote.