The development of the party system in Germany after WorldWarTwo went roughly through three phases: Formative Years, WestGermany / EastGermany and TheBerlinRepublic. Recent developments after the federal elections of 2009 have shook the political spectrum again.
'''''Formative Years''''' (from end of WorldWarTwo to late Fifties)
Shortly after the war ended in 1945, the largest parties were founded (or refounded). These were on the left the '''SPD''' ('''Social Democratic Party''') and '''KPD''' ('''Communist Party''') which both had existed in the WeimarRepublic, while on the right the parties were new: the '''CDU''' ('''Christian Democratic Union''') attracted members from centrists Christians to national conservatives, while the '''FDP''' ('''Free Democratic Party''') attracted members from liberal democrats to national liberals. In Bavaria, the '''CSU''' ('''Christian Social Union''') was founded, and CDU and CSU made an agreement that they would never run against each other. Soon, in the Soviet zone the KPD and SPD were merged to the '''SED''' ('''Socialist Unity Party'''), while in the West they remained separate.
A number of smaller parties were also founded, of special note those founded by people expelled from previously German territories that were annexed by Poland and the Soviet Union (large parts of eastern Poland were also annexed by the Soviet Union, expelling Poles that partially settled in the previously German territories). In the early years of WestGermany, all parties except the KPD demanded the annexed territories back for Germany. This view slowly changed, and after reunification even most of the CDU/CSU opted for friendship with the East European nations instead of making demands.
The formative years ended with a number of developments: the advent of the five percent threshold on federal level caused many small parties to merge with the CDU, the SPD started moving from the left towards the center by dropping Marxist socialism and moving on to Keynesianism, while the KPD was declared anticonstitutional by the Constitutional Court and was dissolved (only one other party was dissolved that way, the Nazist SRP 4 years earlier).
'''''WestGermany''''' (from late Fifties to mid Nineties)
While WestGermany was formed in 1949, its party system reached a stable form about a decade later, when it just consisted of three (or four) parties in the German parliaments:
* CDU/CSU as large party (parties) on the center-right,
* SPD becoming almost as large on the center-left
* the somewhat smaller FDP (usually 5-10%) in the center with both pro-civil rights and pro-business positions.
The West German states were ruled either by either SPD or CDU/CSU, in some cases with absolute majority, in others in coalition with the FDP.
The short "grand coalition" between CDU/CSU and SPD between 1966 and 1969 convinced people on both sides that their side had sold out. On the right, the far-right '''NPD''' was elected to some state parliaments, while on the left, the student movement (68ers) protests flared up (though not as bad as in France), but at first didn't form a party (the communist DKP had the support of the Soviets, but not of the 68ers). Then the "social-liberal" SPD-FDP coalition was formed, and the NPD fortunes waned quickly, while on the left the 68ers tried to create niches for their ideas about society.
Around 1980, large anti-nuclear and pacifist protest movements gave rise to the '''Greens'''. Many groups from far left to far right were involved during the formation, but the party's eventual program was for more social equality, democracy, feminism and individualism and against nuclear energy and NATO.
Other groups left the party, which then developed two wings: Fundis saw their party as a shining beacon people would eventually follow, while Realos wanted to reach actual change in government by compromise. Hardline Fundis eventually left, but a strong left wing remained. Greens were elected into state and federal parliaments, but badly overplayed their hands both after Chernobyl and after reunification, scaring away voters.
In 1982, the FDP switched coalitions and replaced the sitting SPD Chancellor Schmidt with Helmut Kohl from the CDU. In turn, the government turned right and the SPD turned left a little, but couldn't prevent losing some voters to the Greens.
After reunification, the West German party system remained unchanged for a while, and was mostly carbon copied to the East German states.
'''''EastGermany''''' (from Fifties to mid Nineties)
In EastGermany, the ruling communist SED did not dissolve the other parties as the Nazis had done, but instead made them part of the system. These parties (Christian Democrats, Liberal Democrats, National Democrats, and Peasants) always followed the suggestions of the SED, so it didn't matter that the SED nominally didn't have the majority in the East German parliament, the ''Volkskammer'' (People's Chamber). Elections were nominally held, but through arrangements or outright fraud, the power balance never shifted.
There was a "glass ceiling" for members of these parties (nicknamed block parties), but it was not as bad as the one for independents who didn't take part in a major organisation that supported the system.
''Revolution of 1989''
In the fall of 1989, a lot of protest movements were formed or became widely known, and when the East German government finally gave in, a new party system shortly formed for the only free Volkskammer election in March 1990. Among these:
* New Forum, Democracy Now, and Initiative for Peace and Human Rights, which fusioned to the '''Bündnis 90''' (Alliance 90)
* '''Demokratischer Aufbruch''' ('''DA''', Democratic Start)
* '''Deutsche Forum Partei''' ('''DFP''', German Forum Party, whose members had left the New Forum)
* The newly formed '''Social Democrats''', first called '''SDP''', later '''SPD''' like the one in the West
* '''Deutsche Soziale Union''' ('''DSU''', German Social Union, modeled after the Bavarian CSU)
Meanwhile, the SED decided to rename itself '''SED-PDS''' (Party of Democratic Socialism) and took part in the election. Later, they dropped the SED part completely.
The elections were won by the CDU, with the voters wanting to support the western counterpart, not the block party. When reunification was agreed on among both German states and the Allies, a number of party fusions took place:
* CDU (West) merged with the Eastern CDU, the Peasant Party, and the DA
* FDP (West) merged with the Eastern Liberal Democrats, National Democrats and the DFP
* SPD (West) merged with the new Eastern SDP/SPD
* Greens (West) merged with the Eastern Greens and Alliance 90; the current party name still is Alliance 90/The Greens
* PDS (East) did not merge with any Western party (at the time...see below)
* DSU (East) did not merge with any Western party, and mostly faded
In the first years of TheBerlinRepublic, the West German party system was carbon copied to the East, with most restored Eastern states electing CDU governments, mostly in coalition with the FDP.
'''''TheBerlinRepublic''''' (since the mid Nineties)
A few years after reunification, the political pendulum swung back to the left side. First in the states, then on the federal level the SPD won elections. This was actually rather delayed--from shortly after the election of 1987 until late 1989, the Kohl coalition had been steadily declining in the polls and had actually been expected to lose the West German elections expected for 1991, but reunification gave them a few more years of life.
In 1998, a "red-green coalition" of SPD and Greens took office, while also having a majority in the Bundesrat (they lost that in the very next year, though). Red-green was reelected in 2002, partially because of Chancellor Schröder helping when the Oder flood struck and partially because of their rejection to support the USA in a possible Iraq war (modern Germans rather hate war). But on the left, the business-friendly and welfare-cutting "Hartz reforms" (that were made harsher when they needed CDU/CSU-support in the Bundesrat) made red-green unpopular, leading to the formation of the WASG by disgruntled former Social Democrats.
In 2005, CDU/CSU-led state governments got so strong in the Bundesrat they could stop any legislative effort. So Chancellor Schröder arranged to lose a vote of confidence so the President could dissolve the Bundestag and call early elections. The result of these was that neither red-green nor Union-FDP had the necessary majority, so a grand coalition was arrange, led by Angela Merkel (CDU) since the Union was marginally stronger than the SPD. This grand coalition was better liked than the first one in the 1960s and made Merkel popular.
On the left, the 1994 attempt to gerrymander the PDS out of the only constituency they won in 1990 backfired when the PDS nearly doubled their support and won three constituencies, thus giving them full representation in the Bundestag. Being allied with them in any way (whether forming a coalition with them or a minority government tolerated by them) used to carry a large stigma, but this slowly faded over time. After rumours about more constituency victories being necessary for full representation, the PDS finally agreed to merge with the newly formed WASG in the West, and then former SPD chairman Oskar Lafontaine joined in and eventually became chairman of the merged Left Party. In the present, the Left Party is in coalitions with the SPD in Eastern states and tolerates a minority red-green coalition in Germany's largest state, Northrhine-Westphalia, without this having adverse effects in state polls (on the contrary, red-green wouldn't even need the Left Party anymore after fresh elections).
In the early 1990s the rise of Neo-Nazism became a big problem and several parties tried to bring Far Right politics into the Bundestag: Firstly the '''Republikaner''' (Republicans), an offshoot of the CSU who had previously gained 6 seats in the European Parliament in 1989 got 2,1% of the vote in the elections of 1990 (just slightly less than the PDS) and 1,9% in the elections of 1994. With rising competition from further right in form of the '''Deutsche Volksunion''' (DVU) and the re-strengthened NPD the Republikaner faded from view to become a marginalised slighty harsher center-right party. The NPD and the DVU won seats in several East German regional parliaments and were aiming for representation in the Bundestag missing it consistently. After 2004s ''Deutschlandpakt'' which saw the two parties cooperating (along with several smaller parties including the afformentioned DSU) the NPD emerged as the stronger party (mostly because of their ties to smaller Neo-Nazi groups) and draws about 1,5% of the popular vote in the elections to the Bundestag.
An attempt to outlaw the party on the same grounds as the SRP before it failed in 2003 because the Constitutional Court decided that the undercover agents used to gather information about the party were responsible for most of the criminal acts commited tied to the party. The undercover agents inside the NPD have been a high point of debate in German politics, some (including members of the NPD itself) suggesting that the undercover agents are mostly gathering extra money for the NPD and submitting nothing that the police doesn't already now. A second attempt at outlawing the party is currently underway.
'''''Recent Developments''''' (after the 2009 federal elections)
In the 2009 federal elections all three smaller parties gained seats, while the SPD lost big. This resulted in a majority for Union and FDP, and Angela Merkel formed a new Union-FDP government afterwards. But a series of blunders by Union and FDP politicians both on state and federal level followed. On suggestion of the FDP, hoteliers' tax was cut, while the promised tax cuts for the middle class were postponed (and in the end, never came). Then it turned out the FDP got huge donations from hoteliers. Union and FDP lost the majority in Germany's largest state, Northrhine-Westphalia, half a year after the federal elections.
Then the trouble around "Stuttgart 21" started, a billion-euro project to build a new train station and railways underground, while putting areas currently used for railways for development. Opponents said it was much too expensive and that the Deutsche Bahn AG was the only one profiting from it. The state government of Baden-Württemberg supported it. Half a year before the state election the situation escalated when the police used strong water cannons, and protesting high schoolers and pensioners were hit. Then it turned out the police had order to be tough to unmask the protesters as chaots; that backfired immensely, and the government lost support while the Greens, who were against the project, gained.
A mediation by a senior CDU politician calmed down the situation a bit, but then Minister-President Mappus committed the next blunder by buying the EnBW energy producer behind the backs of the state parliament. More expensive than necessary. Negotiated with a personal friend. When in Japan the Fukushima reactor went out of control it was only the last straw: after ruling Baden-Württemberg for decades, the CDU lost power, and the new Minister-President was a Green.
Fukushima also ruined Merkel's plans in other ways: months before, she had made agreements to get out of the red-green arrangement to slowly phase out nuclear energy. She had to reverse course to not lose more popular support, and was still worse off than if she never got out of the red-green plans at all.
And during all the time, the sovereign debt crisis in the Eurozone got worse, and Merkel repeated her behavior a few times: first, she declared that Germany wouldn't help, which raised fears of EU member states becoming insolvent, and then, after the situation had gone worse for some time, she agreed to some form of help, thereby making everyone both in and outside Germany unhappy.
All this had an effect on the political spectrum:
* the CDU/CSU remained relatively stable above a third of the votes, but
* their junior partner FDP, which reached almost 15% of the vote in 2009 now appears around 3% in polls,
* the SPD which had fallen below a quarter of the votes, now slowly catches up to the Union,
* the Greens had passed the SPD in some state and federal polls after winning in Baden-Württemberg, then inched backwards, but still remain a medium-sized party rather than the small one they used to be,
* the Left Party were over 10% in 2009 and are now back below it, and finally
* the Pirate Party rapidly grew after getting 9% in the Berlin state election, and polls show them in federal and some state parliaments if elections were held now; they might get protest votes that otherwise would have gone to the Greens or the Left Party, until they appeared too compromising compared to the Pirates.
In the 2013 election both the SPD and CDU/CSU gained seats at the expense of the smaller parties. With the FDP not in the Bundestag and the Greens having lost seats, neither the CDU nor the SPD could form a traditional coalition (CDU+FDP or SDP+Greens). Although negotiations are still ongoing as of December 2013, it's pretty much given that the SPD and CDU will form a grand coalition government.
The Pirates did not do very well and were not able to increase their share of the vote by all that much. A very different story happened with [=AfD=], a new, anti-Euro party that was formed mostly from disgruntled FDP and CDU voters. [=AfD=] received 4.7% of the vote, not enough to get seats but a good amount considering they weren't a party before April of 2013. Whether [=AfD=] can take advantage of the situation and grow in the coming years or if they'll fall apart as the Eurocrisis becomes less of a major issue remains to be seen.
The situation is still in flux.