This Sunday, there’s a major election coming that will mean big changes to the German government and could have repercussions for Europe. “Come, again?” you might be entitled to ask: “Didn’t the Germans already have a general election just six months ago?” Yes, they did: but now they’re having another one.

The North Rhine-Westphalia Regional Parliament (Flickr: farruska)

Not on a national level, however; no, this is a regional election in North Rhine-Westphalia, Germany’s third largest state in terms of area, and its largest by population. Almost one quarter of all Germans live here, several million of them in major cities like Cologne, Düsseldorf and those of the Ruhr region; and on Sunday, they go to the polls. Although they are only officially voting for their state government, the results will have a major impact in Berlin.

How? After all, whatever happens, Angela Merkel and Guido Westerwelle will continue their coalition government and no one can stop them, right? Of course no one can – they were successful in the national elections – but what voters in North Rhine-Westphalia can do is slow them down, if they chose, or indeed let them go on as before. This is because, in selecting the make-up of their own regional parliament, the Landtag, voters in NRW are also choosing who their state sends to the powerful Bundesrat.

The Bundesrat is the upper house of the German Parliament, through which all laws made in the far better known Bundestag must pass; and whilst it has only a limited law-making capacity of its own, the Bundesrat has the power to stop any law coming up out of the Bundestag dead in its tracks. In this way, it functions very much like the American senate, being part of a system of checks and balances in place to ensure that no one part of the state legislature can act alone.

So any party or parties looking to govern without hindrance (Durchregieren, as it is known German) needs control not only of the Bundestag but also of the Bundesrat, and that is easier said than done. Firstly, because regional governments tend to be more stable than national ones – whatever happens on a national level, Bavaria and Saxony are almost guaranteed to remain CDU/CSU governed, whilst Rhineland-Palatinate and Brandenburg, for example, have been consistently red. So whilst a party may fare poorly nationally, its core geographical base will almost never desert it.

Even Lower Saxony, with its population of under 10 million, has a large Neoclassical Landtag (Flickr: pittigliani2005)

The second factor that makes the Bundesrat difficult for the government is that, in the “swing states” where either party can win, a regional election can be used to punish unpopularity and delay measures that do not have majority support. And since the different states go to the polls at different times, the disgruntled voter never has to look far for an opportunity to knock the government down a peg or two.

And it is a combination of these two points that makes Sunday so fascinating for politics nerds in Germany – and so confusing for those of us not familiar with the ins and outs of the German electoral system. Historically, North Rhine-Westphalia is a left-leaning state, spending the 35 years up until 2005 in SPD hands; the change to the current CDU-FDP coalition under Jürgen Rüttgers was unexpected and robbed the SPD chancellor Gerhard Schröder of his majority in the Bundesrat, essentially stymieing his government in Berlin and forcing him to call new elections to try and recover legitimacy.

Hamburg's town hall is more than just a mayor's talking-shop: Hamburg sends a delegation to the Bundesrat too (Flickr: arne_list)

Five years later, the shoe is on the other foot, with Angela Merkel heading up a national government that has become unpopular in some quarters and which some voters may be looking to punish. Those of them who switched their allegiance from the SPD to the CDU in 2005 might be ready to switch back, and if they do, Merkel’s CDU-FDP coalition will no longer have control of North Rhine-Westphalia, and thus no longer have control of the Bundestag Bundesrat [Update 06/05/2010, thanks to FT]. Any measures the Chancellor would then initiate would have to win the support of the other side of the political spectrum in order to be passed into law.

All of which could make the whole business of governing somewhat challenging. When my home country goes to the polls tomorrow, they will be offering their politicians a mandate for 5 years; and if they realize a few years in that this was a mistake, then I’m afraid that’s just hard cheese. Americans and the French, however, are quite familiar with the concept of chiding their government through mid-term elections, and so will understand the importance of May 9 for the whole of Europe – well, at least more quickly than your average Brit.

And I for one think it’s a superb idea. It might make life more difficult for politicians, but the kind of multi-stage democratic system that Germany runs is one that responds to the voters and allows them to keep regular tabs on their government. That’s democracy if ever I saw it.