Christian Social Union of Bavaria in the context of "Political party in Germany"

The Federal Republic of Germany has a plural multi-party system. Historically, the largest by members and parliament seats are the Christian Democratic Union (CDU), with its sister party, the Christian Social Union (CSU) and Social Democratic Party of Germany (SPD). Germany also has a number of other parties, in recent history most importantly the Free Democratic Party (FDP), Alliance 90/The Greens, The Left, and more recently the Alternative for Germany (AfD). The federal government of Germany often consisted of a coalition of a major and a minor party, specifically CDU/CSU and FDP or SPD and FDP, and from 1998 to 2005 SPD and Greens. From 1966 to 1969, from 2005 to 2009, from 2013 to 2021 and since 2025, the federal government consisted of a coalition of the two major parties, called a grand coalition.

Coalitions in the Bundestag and state legislatures are often described by party colors. Party colors are red for the Social Democratic Party, green for Alliance 90/The Greens, yellow for the Free Democratic Party, purple (officially red, which is customarily used for the SPD) for the Left, light blue for the AfD, and black and blue for the CDU and CSU respectively.

A federal election was held on 22 September to elect the members of the 18th Bundestag of Germany. At stake were all 598 seats to the Bundestag, plus 33 overhang seats determined thereafter. The Christian Democratic Union of Germany/Christian Social Union of Bavaria (CDU/CSU) of incumbent chancellor Angela Merkel won their best result since 1990 with nearly 42% of the vote and nearly 50% of the seats, just five short for an overall majority. The co-governing Free Democratic Party (FDP) failed to meet the 5% vote electoral threshold in what was their worst showing ever in a federal election at the time, the electoral wipeout denying them seats in the Bundestag for the first time in their history.

As the CDU/CSU's narrowly missed a majority, and the FDP failed to get any seats, any prospective government was required to be a new coalition. The only possible coalition government excluding the CDU/CSU would have been an all-left-wing red–red–green coalition, since a red–green alliance, similar to the German government between 1998 and 2005, would not have enough seats for a majority. Both the Social Democratic Party of Germany (SPD) and Alliance 90/The Greens ruled out governing with The Left that had ruled former East Germany. Ultimately, Merkel's party reached a coalition agreement with the then-main opposition party, the SPD, to form another grand coalition, the third in the country's history since World War II. The SPD leadership conducted a ratification vote by their broader membership before the agreement was made final. This grand coalition was renewed after the 2017 German federal election due to failure during the negotiations of a Jamaica coalition.

A federal election was held in Germany on 24 September 2017 to elect the members of the 19th Bundestag. At stake were at least 598 seats in the Bundestag, as well as 111 overhang and leveling seats determined thereafter.

The Christian Democratic Union of Germany and the Christian Social Union of Bavaria (CDU/CSU), led by incumbent chancellor Angela Merkel, won the highest percentage of the vote with 33%, though it suffered a large swing against it of more than 8%. The Social Democratic Party of Germany (SPD) achieved its second worst result since post-war Germany at 21%, undercut only by its 2025 result. Alternative for Germany (AfD), which was previously unrepresented in the Bundestag, became the third party in the Bundestag with 12.6% of the vote, whilst the Free Democratic Party (FDP) won 10.7% of the vote and returned to the Bundestag after losing all their seats in 2013. It was the first time since 1957 that a party to the political right of the CDU/CSU gained seats in the Bundestag. The other parties to achieve representation in the Bundestag were the Left and Alliance 90/The Greens, each close to 9% of the vote. In the 709 member Bundestag, a majority is 355 and the CDU/CSU won 246 seats (200 CDU and 46 CSU), the SPD 153, the AfD 94, the FDP 80, The Left 69, and the Greens 67.

In German politics, a grand coalition (German: Große Koalition [ˈɡʁoːsə koaliˈt͡si̯oːn] , shortened to: German: Groko [ˈɡʁoːkoː] ) is a governing coalition between the two parties with the most parliamentarians on federal or state level. The term is generally linked to a coalition between the centre-right CDU/CSU alliance (Union, consisting of the Christian Democratic Union (CDU) and Christian Social Union of Bavaria (CSU) parties) and the centre-left Social Democratic Party (SPD), since they have historically been the major parties in most state and federal elections since 1949. The meaning of the term changed due to the growth of some formerly minor parties in recent years. It is the current governing coalition of Germany under the Merz cabinet following the 2025 federal election, and marks the first time that one of the two parties does not have the most or second most seats in the Bundestag (the AfD won the second most seats). Therefore, the latest coalition between CDU/CSU and SPD is often instead described as a black-red coalition, referring to the respective colors of the two blocs. If the coalition also includes the liberal Free Democratic Party (FDP), it is called a "Germany coalition" (German: Deutschland-Koalition (de)), with the party colors matching the flag of Germany: black for CDU/CSU, red for SPD and yellow for FDP.

A federal election was held in Germany on 18 September 2005 to elect the members of the 16th Bundestag. The snap election was called after the government's defeat in the North Rhine-Westphalia state election, which caused them to intentionally lose a motion of confidence to trigger an early federal election. The outgoing government was a coalition of the centre-left Social Democratic Party of Germany (SPD) and Alliance 90/The Greens, led by federal chancellor Gerhard Schröder. The election was originally intended for the autumn of 2006.

The opposition Christian Democratic Union of Germany (CDU), with its sister party the Christian Social Union in Bavaria (CSU), started the campaign with a strong lead over the SPD in opinion polls. The government was generally expected to suffer a major defeat and be replaced by a coalition of the CDU/CSU and the liberal Free Democratic Party (FDP), with CDU leader Angela Merkel becoming chancellor. However, the CDU/CSU ultimately lost vote share compared to its 2002 result, falling to 35%. The SPD suffered losses but finished just one percentage point behind the CDU/CSU, winning 34%. Exit polls showed clearly that neither the SPD–Green nor CDU/CSU–FDP coalitions had won a majority of seats in the Bundestag. The FDP placed third on just under 10% of votes, its best result since 1990, while the Greens suffered small losses. The major stumbling block to a parliamentary majority was the new Left Party, led by Gregor Gysi and former SPD chairman Oskar Lafontaine, which won 8.7% of votes and 54 seats. The CDU/CSU and SPD both rejected cooperation with the Left Party.