In one of his many excellent pieces in the run-up to the German election, Alex mentioned the phenomenon of ‘overhang mandates’. These are extra parliamentary seats that a party gains by winning more seats via one of German’s two electoral methods than by the other. This might seem odd enough. What’s even odder is that a party could lose a seat if too many people vote for it.
German electoral law is complex. In a comment to one of Tobias’s posts, Florian recommended the wahlrecht.de website as a good primer on how it works. He also mentioned examples of some of the electoral weirdnesses explained by wahlrecht.de. For example, did you know (asks Florian) that, under certain circumstances, a vote can have ‘negative weight’ — can reduce the parliamentary representation of the party for which it is cast?
Well, it can. And this conundrum is worth looking at closely, because right now it is more than a mere electoral curiosity. There is one electoral district in Germany, Dresden I, that has not yet voted. (Those who’ve been paying a perhaps unhealthy level of attention to the German elections will know that the death of a neonazi candidate has forced the delay of the election.) And in Dresden I, there is a very real chance that a local triumph of the CDU could cause the party to lose a seat in the national parliament. The reason? It’s those overhang mandates that Alex kept mentioning.
Excellent as wahlrecht.de is, it’s in German. Below the fold, then, is a summary explanation of how the CDU could lose a seat by gaining votes. For those who read German and are interested in that sort of thing, there are links to the relevant passages of the BWahlG (German Federal Electoral Act).
In the mean time, we should note that the possible ‘negative weight’ of CDU votes in Dresden I, though perverse and undemocratic, would not affect the overall results in Germany. Even if the CDU are ‘catastrophically successful’ in Dresden I, the Union will still have more seats than the SPD, albeit with a lead of only 2 rather than 3 MPs. The really perverse thing that could come out of the Dresden special election is this: CDU and SPD wind up with an equal number of seats. As the Spiegel explains, however, this is mathematically a possibility, but in real-world terms exceedingly unlikely. To achieve this result, the SPD would need to poll 91% of voters in the district, and every single eligible voter would have to vote.