section_path: Background/Electoral system/2023 reform
section_name: 2023 reform
paragraph_text: 2023 reform
  
  Before the 2025 election, if a party won constituencies in a state exceeding its proportional entitlement, it could keep the so-called overhang seats, which consequently increase the size of the Bundestag. This problem was compounded by a 2008 ruling by the Federal Constitutional Court, and a subsequent electoral reform, which introduced leveling seats be added for other parties to keep the composition of the Bundestag proportional. Consequently, the 2017 and 2021 elections saw large numbers of additional seats.
  
  After the 2021 election produced a Bundestag with 736 members – making it the largest freely elected parliament in the world – renewed debate began over the system that had been in place since the 2013 election. The Bundestag passed a reform law in March 2023 to fix the size of any future Bundestag at 630 members. It introduced two significant changes:
  
  The principle of second vote coverage means that parties are no longer allowed to keep overhang seats; if a party wins overhang seats in a state, its constituency winners are excluded from the Bundestag in decreasing order of their first vote share. The three-constituency rule stipulates that if a party does not pass the 5% threshold but wins a plurality of votes in 3 constituencies, it is eligible for list seats. If a party wins one or two constituencies but does not pass the threshold – a scenario which has only happened once, to the PDS in 2002 – those winners are also now excluded and not elected as they would lack second vote coverage. However, the principle does not apply for independent candidates. If an independent wins a constituency (which has not happened since 1949), the candidate is still elected.
  
  Both the CSU and The Left opposed these changes. In the 2021 election, The Left fell short of the five percent threshold but remained as a faction in the Bundestag because it won three constituencies. In contrast, the CSU barely crossed the threshold with 5.2% of the nationwide second vote while winning 45 of the 46 constituencies in Bavaria. The CSU was also the only party to win overhang seats in that election. Both parties appealed to President Steinmeier to veto the proposed changes; nevertheless, Steinmeier signed the bill after his office concluded it was constitutional. Both party organizations and the government of Bavaria, controlled by the CSU, filed formal complaints to the Federal Constitutional Court.
  
  Hearings were held on 23 and 24 April 2024. On 30 July 2024, the court largely upheld the new electoral law. However, it ruled that a five-percent threshold without any exceptions is unconstitutional; though it recognized the threshold is necessary to prevent fragmentation, it held there must be measures to minimize wasted votes. To settle electoral law in sufficient time for this election, as an interim measure, the court re-introduced the basic mandate clause as it was "until there is a new regulation on the matter." As such, a party getting a plurality of first votes in at least three constituencies would still enter the Bundestag, obtaining seats in proportion to its national second vote share.