It's the smallest state, with just 664,000 inhabitants, or .8% of the population of the country as a whole. And, just as importantly, it has no rural population. The three city-states - Bremen, Hamburg, and Berlin - naturally lean left.

The significance of these elections doesn't derive from Bremen being representative of the rest of the country. It's largely symbolic (although in case the SPD forms a new red-green coaltion in Bremen, this would mean Merkel looses her two-third majority in the second chamber, the bundesrat, and as a result won't be able to operate there quite as unimpeded).

If you can't convince them, confuse them. (Harry S. Truman)