The number of MPs can be capped only by relinquishing overhang(and compensation) mandates in a system of proportional representation. Nevertheless, mechanisms should be found to compensate for the impending loss of constituency offices, so that local points of contact with parliamentary representatives are guaranteed in all 299 constituencies. One idea would be to consider how the co-supervision of those affected constituencies by MPs from neighbouring constituencies, which is already prac­tised by many parties, can be encouraged. Decline in the number of marginal constituencies The marked changes in the German party system in recent years, with more parties represented in the Bundestag and greater competition between them, has had the logical consequence that constituencies can often be won with a comparatively small number of votes. Looking at constitu­encies in which the difference between the first- and sec­ond-placed candidates was less than 5 per cent, there were 64 marginal constituencies in the 2017 federal election. Four years later, there were already 100 marginal constitu­encies. This means that in the 2021 federal election, one in three constituencies was won by less than 5 per cent in the first votes. In the 2025 Bundestag election, by contrast, there were only 65 constituencies in which the gap between direct candidates was narrow. This means that the level of the 2017 Bundestag election has more or less been reached again. Nevertheless, it is clear that there were often very close races, particularly in metropolitan constituencies and in university towns. In the electoral district of Stuttgart I, for example, the Green Party candidate won by just 16 first votes over her CDU rival, according to the preliminary final result. The electoral districts of Berlin-Tempel­hof-Schöneberg, Goslar-Northeim-Göttingen II and Cologne III were also very close. In 2021, the SPD was still usually able to prevail in marginal constituencies, but this time the CDU managed to win 29 marginal constituencies. The SPD won 22 marginal constituencies. The Greens were able to increase the number of marginal constituencies won to nine. Die Linke won the Berlin-Friedrichshain-Kreuz­berg-Prenzlauer Berg Ost constituency by 4.1 percentage points, while the AfD came out just ahead in four urban constituencies(Berlin-Marzahn-Hellersdorf, Rostock-Land­kreis Rostock II, Dresden I and Leipzig I). The CSU won in the Bad Kissingen constituency by 36 per­centage points, the largest margin between first and sec­ond place winners in the 2025 federal election. In Bavaria and North Rhine-Westphalia in particular, the Christian Democratic Union and Christian Social Union were able to win by a large margin in many constituencies. Many AfD direct candidates often managed this in the east. But the SPD and Die Linke also continue to have first-vote strong­holds. Comparing the maps of marginal constituencies in the 2021 and 2025 federal elections, several developments stand out. First, the number of close constituencies in east­ern Germany has decreased, with a few exceptions. This is because of the strong performance of the AfD, which won almost all direct mandates in the eastern part of the coun­try. Secondly, small but densely populated urban constitu­encies remain particularly contested. Increasingly, even smaller parties can win a direct mandate there. Third, safe first-vote strongholds continue to exist. Nevertheless, the pattern also changes dynamically over time: formerly tight constituencies can be won comfortably again, depending on the situation, while in some regions strongholds crum­ble and election victory can be secured only by a narrow margin. Party affiliation of winners in marginal constituencies Party affiliation CDU/CSU SPD Greens Linke AfD Total 2017 30 30 1 1 2 64 2021 41 44 7 1 7 100 Source: Federal Returning Officer, own calculation. 2025 29 22 9 1 4 65 ‌Tab. 1 Analysis of the Bundestag elections 2025 21