The German state of Baden-Württemberg held its state legislative election this past Sunday, 8 March 2026. The incumbent government is headed by Winfried Kretschman of the Green Party in coalition with the Christian Democratic Union (CDU). The latter is the party of the federal Chancellor Friedrich Merz. The government following this election is sure to be a continuation of this two-party coalition, now with new Greens leader Cem Özdemir at its head.
In addition to reviewing the election outcome under the mixed-member proportional (MMP) rules in place–which were reformed prior to this election–this planting will also consider how some alternative rules, including other variants that remain MMP but are not as fully proportional, would have worked.
In the voting result, the two parties were almost tied, with the Greens on 30.2% and the CDU on 29.7%. In third place is the far-right Alternative for Germany (AfD) on 18.8%, followed by the Social Democrats (SPD) on a mere 5.6%. The legal threshold for winning any list seats is 5% of the party vote, and no other parties cleared it. This year’s result is actually a substantial gain for the CDU compared to the state’s election of 2021, when it had 24.1%, and a small decline for the Greens, who had 32.6% in the preceding election. These vote figures are not fully comparable across years, for reasons having to do with the electoral reform, discussed later.
A table at Wikipedia has the full 2026 results, broken down by list and nominal (constituency) vote, given the mixed-member proportional (MMP) system in use. Interestingly, the CDU did quite a lot better in the nominal vote, with 34.3% to the Greens’ 25.5%. Unlike the reformed national system, the B-W system still has the possibility of increasing the total size of the assembly in the event that there are “overhangs” from a party having earned more constituency seats than what its proportional entitlement should be. In addition, like the former federal rules, the B-W rules still allow for the possibility of further “leveling” seats to restore full proportionality (for above-threshold parties).
In nominal seats, the CDU won 56 of the 70 total. The assembly has a minimum size of 120 seats, implying 50 list seats. According to the brief description at Wikipedia, the law requires proportionality statewide. The CDU’s 56 constituencies won would already be almost 47% of the minimum 120 seats, which would be a substantial overrepresentation given their 29.7% of the list vote (which, as noted, was a second-place finish). Thus the CDU is entitled to no list seats, given that MMP mandates these be allocated as compensatory seats (not in “parallel” as in the other main type of mixed-member system, MMM–see Japan’s recent election, for example). [Deleted from this paragraph was an earlier point about proportionality also being required across administrative district. See comment by Thomas for correction.]
Other parties, however, need compensations seats, and the mandated full proportionality can be achieved only by a substantial increase in the size of the assembly, which will have 157 seats. In the final result, the Greens win 43 list seats in addition to the mere 13 districts they won. This total of 56 puts them on par with the CDU, whom they essentially tied in party-list votes. It also leaves each of the two large parties on 35.7% of the total expanded assembly. Given that 15.75% of votes were cast for parties below the legal threshold, the Greens and CDU each have approximately 35.6% of the above-threshold vote. Thus indeed full proportionality has been restored through the allocation of the expanded pool of compensatory list seats.
As for the other parties, only one nominal-tier seat was won by a party other than the top two. This was an AfD seat, and that party’s 18.8% of the total vote translates to 22.3% of the above-threshold vote. It has been allocated 34 list seats to go along with its one constituency seat, and that total of 35 is, yes, 22.3% of the total 157. The only other seats allocated are 10 list seats to the SPD.
Now I want to turn to potential alternative ways in which seats could have been allocated and still be consistent with the principles that define MMP, as well as one that would not be.
The system would still be MMP, albeit less fully proportional, even if there were no expansion of the size of the assembly to deal with the overhang. If the number were fixed at 120, with 70 single-seat constituencies and 50 compensatory list seats, the CDU’s 56 constituency victories would have been 46.7% of incoming assembly. The three other parties that cleared the party-vote threshold would have split the 50 list seats. There are various ways this might be calculated, but a straightforward way if we want a simple estimate* is to recalculate list vote shares for only those parties that are entitled to list seats. The parties that are not so entitled obviously include those that are below the list-vote threshold. Also included among such parties are any that already have obtained at least their proportional entitlement in the nominal tier. In our case, that means we exclude the CDU votes in addition to all those below the threshold. When we do this, the recalculated vote shares of parties eligible for list seats are: Greens 0.554, AfD 0.345, and SPD 0.102. These shares are applied not to the total 120 seats, but to the number of seats remaining to be allocated, which in this case is 64: our fixed number of 120, minus the 56 already credited to the CDU from the nominal tier. When we apply these adjusted vote shares for parties eligible for list seats, we get approximately1 35 seats for the Greens, 22 for the AfD, and 7 for the SPD. Some of these parties already have nominal seats, so their list seats will be these adjusted entitlements, minus nominal seats: Greens 22 (because they won 13 districts), AfD 21 (they have one nominal seat), and finally the SPD which gets all of its seats from the list (7). The resulting percentages of the full 120 seats would be: Greens 29.2%, CDU 46.7%, AfD 18.3%, SPD 5.8%. [*See footnote #1 (second paragraph) for a more detailed way that is probably more accurate.]
Recall that the Greens obtained 30.2% of the list vote, which was a plurality. They are somewhat underrepresented in this scenario, with an advantage ratio (%seats/%votes) of only 0.966. The CDU’s 56 seats give them an advantage ratio of 1.57, and those of the other two parties are 0.975 (AfD) and 1.05 (SPD). These differential advantages ratios (1.00 would be pure proportionality) are due to the overhang, as well as the lack of any seats to be added in response to those overhangs. This is assuredly MMP, and the result is far more proportional than if there were only single-seat districts (the CDU, after all, won 80% of those!) or if it were mixed-member majoritarian (under which the CDU still would have won list seats–probably 15 of the 50) despite having won so many districts.
An intermediate approach between the model just sketched and the actual procedure would be to add seats to the list tier for each overhang, but no further “leveling” seats beyond those. This would be similar to how the New Zealand MMP system works (see in 2023 or 2008). In this scenario, because the CDU has 14 overhangs (as we shall see), the assembly would be increased from 120 to 134 seats. The resulting 64 list seats would be used to compensate the other parties. Under this procedure, each party that does not have an overhang still gets the same number of seats it would have had in the absence of the overhang. Given the parties’ shares of the above-threshold vote, the seats should be, under the no-overhang scenario: Greens 43, (CDU 42), AfD 27, SPD 8. The CDU’s share shows us where the 14 overhang seats come from, given it actually won 56 single-seat districts. Because of the nominal seats won, these imply list seats for these parties of Greens 30, (CDU 0), AfD 26, SPD 8. Note that these sum to 64 list seats–the baseline of 50, plus the 14 added in response to the overhangs. In terms of seat percentages (and advantage ratios), we now have Greens 32.1% (1.06), CDU 41.8% (1.41), AfD 20.1% (1.07), and SPD 6% (1.08). All parties are now slightly overrepresented (advantage ratio over 1.00), but the CDU remains substantially more overrepresented than the others. The MMP system still effectively rewards it for having many candidates who could win districts, yet it does not cut any other above-threshold party’s number of seats from what it would have been in the absence of overhang. The shares are still reduced relative to the no-overhang situation, because there are no further “leveling” seats added to restore full proportionality, as there are in the actual system in use in B-W.
And then there is yet another possible solution to the overhangs. The CDU could be required to give them up, and the 14 weakest of their 56 districts would be left without local representation,2 leaving full proportionality to be achievable for all above-threshold parties out of the original 120 seats. Note that this is utterly inconsistent with the principle behind MMP, which is that candidates hold seats if they have been able to win the local plurality, and parties win proportional representation up to the limits of the total seats available (expanded, as necessary and permitted under the rules). This is the reason why I no longer consider the federal system of Germany to be a mixed-member system. It violates the key principle that the nominal tier results are decisive. It is instead a form of PR with constituencies serving as a local-nominating and overall intraparty ranking mechanism. B-W, however, retains a very pure form of MMP, with maximum proportionality (for above-threshold parties) as its design goal.
As alluded to earlier, this system is itself a recent reform, passed after the 2021 election. B-W used to have no separate party list. Instead, the compensation seats were awarded to the best-performing constituency candidates who did not win local pluralities. Again, this is fully consistent with MMP, and we could say simply that the compensatory “list” is composed of constituency-nominated candidates who are non-winners by that tier. (The 2021 system also had added compensatory seats in case of overhang and additional “leveling” seats to restore proportionality, like the 2026 system. That is, how the list is constructed and whether there is a separate vote for it are separate dimensions of MMP from how the system deals with overhangs.)
Because there was only a single vote in 2021, arguably a direct comparison of vote changes between these elections is not straightforward. In 2021, a voter could vote for the “list” of a preferred party only by voting for the party’s constituency candidate. If we compare nominal votes for constituency candidates in 2026 to the 2021 fused vote, the CDU gained over ten percentage points (34.3% from 24.1), while the Greens fell by 7.1 (32.6% to 25.5%). If we compare across list votes it is +5.6 for CDU and –2.4 for Greens. Which is the better comparison? Arguably we can’t know. Voters under single fused-vote MMP must make a choice between endorsing their preferred local representative or their preferred party (if these are different for a given voter), and that means some may vote for a a small party with no chance of winning their district in order to boost its overall seat total via compensation. Others may vote for a candidate even if they do not really like the party, simply because they want that local representative. This is why I think one-vote MMP undermines the “best of both worlds” potential of MMP! However we look at the cross-election change, the CDU gained and the Greens lost, yet both will remain in coalition and the Greens presumably will retain the state’s Minister-President position on account of their narrow plurality of the separate list vote.
The voters indeed did take advantage of the ticket-splitting option. The effective number of vote-earning parties was 4.50 in 2026 in list votes, which is higher (albeit not by a lot) than the effective number on nominal votes, which came in at 4.34. The effective number on seats is a good deal lower, due to the large below-threshold vote, at 3.24.3 In 2021, the effective number of parties via votes was 5.01 and seats 3.89. The 2026 result is less fragmented (lower effective numbers) because the votes and seats are more dominated by the top two parties, even if those two combined for not quite 60% of the total votes and barely over 70% of the seats.
Regarding the legal threshold, two parties obtained over 4% of the list votes but below the mandated 5%. The Left Party won 4.41% and the Free Democratic Party (FDP) won 4.38%. No other party won over 2%. As I have noted before, it is quite possible that the 5% threshold is now too high for the party system that Germany and its states actually have, and that it should be lowered to 4% or even 3% or lower to avoid such a high total of wasted votes.4 The wasted votes were close to a sixth of the total, and would have been cut by more than half had the threshold been 4%. Having the Left and FDP in this assembly almost certainly would not have changed what governing coalition could form based on this result. But in other cases, it could have such an effect.
I always enjoy looking at the list of also-rans, the parties that fall far below a legal threshold. In this election, my favorite might be the “Party for Rejuvenation Research,” which earned 3,590 list votes (0.07%).
The Baden-Württemberg election of 2026 results in a tie in seats for the top two parties, Green and CDU, because (1) those parties had almost tied list-vote shares, and (2) the rules of MMP in use provide for additional seats to correct for overhang and further additional “leveling” seats to restore full proportionality for parties that clear the list-vote threshold. There are, however, other potential means of handling such a large overhang as the 14 CDU seats that were above its proportional entitlement, and two of those that we have reviewed remain within the parameters that define MMP. A third one we reviewed–which would be similar to that used since 2025 in federal elections in Germany–would be outside the family, as strictly defined. Baden-Württemberg is one of several German states holding elections in this Superwahljahr. Most German states use MMP, with some variation in the details of system design that we may explore further as these upcoming elections occur.
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