Overhang mandates

Germany's election system is a mixed first-past-the-post/proportional one, with the latter dominating. Everyone has two votes: one for an individual candidate in the local election district, and another for a party list in the Land (state) the district is in.

Simplifying the process a bit, every state has about twice as many seats to distribute as it has individual election districts, so once the winners of the latter are known, the rest of the vacant seats are filled up from the party lists, so that the overall ratios are according to the second votes.

To give you an example: say a state has 8 districts. The Black Party wins five, the Red Party three seats directly. But meanwhile, party list votes are Black Party 42%, Red Party 36%, Green Party 18%, other 4%. That means Black is entitled to 7 seats, so two more can come from the party list; Red is entitled to 6 seats, so three more can come from the list, and Green gets 3 seats, all from the list.

However, it may happen that a party wins more seats directly than what proportional vote would entitle it to. In that case, all other parties still get their fair share according to the original calculation, so the lucky party has more seats than would be proportional, and the entire parliament increases from its minimum size by these overhang mandates.

In the above example, this would be the case if the Black Party would win all 8 direct mandates while the party list vote would stay the same: it would be entitled proportionally to 7 seats but would have one more, while no one would follow from the list; while the Reds and Greens would get all six resp. three seats filled from their lists.

Merkel's melting majority

In the 2005 elections, the Christian Democrats (CDU), which ran party lists and candidates in 15 of the 16 Länder, together with their permanent partners, the Christian Socialists (CSU, which runs in Bavaria) won 35.17% of valid party list votes. Their partners in the resulting 'Grand Coalition', the Social Democrats (SPD) won 34.25%.

Proportionally, this would have resulted in 219 vs. 213 seats. However, while CDU+CSU won only 7, the SPD won 9 overhang mandates, so the former's advantage in seats was narrower: 226:222. Still, a majority is a majority, so the CDU's Angela Merkel became chancellor (head of government).

Then, there was a scandal over the far-right remarks of a representative from CDU stronghold Saxony, who then left the party (this was diaried here). This man was the winner of a direct mandate, and the CDU had three overhang mandates from Saxony, so CDU couldn't 'replace' him from the party list -- thus Merkel's majority reduced to 225:222.

Now, on 26 March this year, influential economic liberal CDU member Matthias Wissmann (he used to be R&D and transport minister under Helmut Kohl, and is a member of the infamous old boy network Andenpakt, see here) was elected head of the German Automobile Industry Association (Verband der Automobilindustrie, VdA). His predecessor was pressured to resign for failure in lobbying Merkel to (further) reduce planned future environmental/climate change requirements... Pre-empting accusations of interest conflict (scandals recently plagued the CDU), in the end he announced that he'll step down as representative once he takes office as VdA head, which happened on 1 June.

However, Wissmann was directly elected in another CDU stronghold, Baden-Württemberg (see a story here): so another overhang mandate lost, so it's 224:222.

End of next week, on 17 June, the city of Mannheim will elect a new major. The CDU candidate is poised to win. He happens to be another Baden-Württemberg direct mandate holder in parliament, and will step down: so one more overhang gone, it will likely be 223:222.

A further reduction is not unlikely. As analysed by Walrecht.de, what we should focus on is not the relative number of overhang mandates, but the pool for overhang mandate losses: e.g., all direct mandate wins in states from where parties got overhang mandates. And there, the SPD has an advantage: it collected more overhang mandates in smaller states.

After a CDU victory in Mannheim, the situation would be:

• SPD: 30 direct mandates from four Länder of which 9 are overhang mandates
  
• CDU: 44 direct mandates from two Länder of which 4 are overhang mandates

Recent polls

Wolfgang Munchau can fear further. The effect of the Left swing in Bremen is still visible in the last polls, the three left-wing parties would have a majority, and the one trend that seems visible in all pollsters' polls is some strengthening of the hard-left Left Party and some weakening of the (presently neo)liberal FDP.