Does anyone “out there” know of a case under a mixed-member proportional (MMP) system in which “overhang” seats were responsible for a manufactured majority? Or determined which potential coalition could form after the election?
I have a vague recollection that there was a German federal election in which one of the coalitions’ ability to form was shaped by overhang seats. I also know that the last Scottish election featured a manufactured majority, but I am not sure if the mixed-member provisions, per se, were the cause, or if the small size of the regions in which compensation is carried out would have been sufficient to produce the outcome.
By “manufactured majority” I mean more than half the seats for a party (or pre-election alliance cooperating in the district races) that had less than half the votes.
By “overhang” I mean… what, exactly? It seems some folks use the term to refer to any case of a party having more seats via the (nominal) district contests than its proportional entitlement would have been, while other folks mean additional seats added to the legislature as a response to such district wins. Either way, the question is of interest.
The question arose out of a conversation I was having with John Carey, who passes along a much more thoughtful version of the question, which I am posting here:
Can anyone identify a case where a less-than-fully-compensated overhang produced a parliamentary majority in an instance where a fully-compensated overhang (or just a fully proportional election) would not have?
Explanation: The question refers to mixed-member compensatory systems, like those used in Germany, New Zealand, or Bolivia. In instances where a given party wins more seats in the SMD tier than its list PR vote would warrant, the excess seats are referred to as “overhang” seats. Overhangs can be dealt with various ways:
Overhang Expansion: The party with the overhang keeps its excess seats. Other parties are awarded the number of seats each would be entitled to according to its share of the list PR vote. The size of the parliament is increased by the number of overhang seats. (Example, Germany before 2013.)
Full Compensation: The party with the overhang keeps its excess seats. All other parties are also awarded additional seats such that the overall distribution of seats achieves full proportionality. Parliament is thus enlarged both by the overhang seats and by the additional seats given to other parties in order to balance the overhang. (Example: Germany as of the 2013 election, following the Constitutional Court-mandated reform of 2011.)
Non-Expansion: The party with the overhang keeps its excess seats. Seats to which some other party or parties would be entitled, according to their share of the list PR vote, are not awarded to them in order to maintain the size of parliament at a fixed number of seats. (Example: Bolivia)
So, effectively, the question is whether use of either the first (Overhang Expansion) or third (Non-Expansion) method yielded a winner’s bonus that produced a parliamentary majority that would not have prevailed had Full Compensation been used.