Christian Social Union in Bavaria

Chairman Franz Josef Strauß in 1976

Franz Josef Strauß (1915–1988) had left behind the strongest legacy as a leader of the party, having led the party from 1961 until his death in 1988. His political career in the federal cabinet was unique in that he had served in four ministerial posts in the years between 1953 and 1969. From 1978 until his death in 1988, Strauß served as the Minister-President of Bavaria. Strauß was the first leader of the CSU to be a candidate for the German chancellery in 1980. In the 1980 federal election, Strauß ran against the incumbent Helmut Schmidt of the Social Democratic Party of Germany (SPD) but lost thereafter as the SPD and the Free Democratic Party (FDP) managed to secure an absolute majority together, forming a social-liberal coalition.

The CSU has led the Bavarian state government since it came into existence in 1946, save from 1954 to 1957 when the SPD formed a state government in coalition with the Bavaria Party and the state branches of the GB/BHE and FDP.

Initially, the separatist Bavaria Party (BP) successfully competed for the same electorate as the CSU, as both parties saw and presented themselves as successors to the BVP. The CSU was ultimately able to win this power struggle for itself. Among other things, the BP was involved in the "casino affair" under dubious circumstances by the CSU at the end of the 1950s and lost considerable prestige and votes. In the 1966 state election, the BP finally left the state parliament.

Before the 2008 elections in Bavaria, the CSU perennially achieved absolute majorities at the state level by itself. This level of dominance is unique among Germany's 16 states. Edmund Stoiber took over the CSU leadership in 1999. He ran for Chancellor of Germany in 2002, but his preferred CDU/CSU–FDP coalition lost against the SPD candidate Gerhard Schröder's SPD–Green alliance.

In the 2003 Bavarian state election, the CSU won 60.7% of the vote and 124 of 180 seats in the state parliament. This was the first time any party had won a two-thirds majority in a German state parliament.[15] The Economist later suggested that this exceptional result was due to a backlash against Schröder's government in Berlin.[16] The CSU's popularity declined in subsequent years. Stoiber stepped down from the posts of Minister-President and CSU chairman in September 2007. A year later, the CSU lost its majority in the 2008 Bavarian state election, with its vote share dropping from 60.7% to 43.4%. The CSU remained in power by forming a coalition with the FDP. In the 2009 general election, the CSU received only 42.5% of the vote in Bavaria in the 2009 election, which by then constituted its weakest showing in the party's history.

The CSU made gains in the 2013 Bavarian state election and the 2013 federal election, which were held a week apart in September 2013. The CSU regained their majority in the Bavarian Landtag and remained in government in Berlin. They had three ministers in the Fourth Merkel cabinet, namely Horst Seehofer (Minister of the Interior, Building and Community), Andreas Scheuer (Minister of Transport and Digital Infrastructure) and Gerd Müller (Minister for Economic Cooperation and Development).

The 2018 Bavarian state election yielded the worst result for the CSU in the state elections (top candidate Markus Söder) since 1950 with 37.2% of votes, a decline of over ten percentage points compared to the last result in 2013. After that, the CSU had to form a new coalition government with the minor partner Free Voters of Bavaria.

The 2021 German federal election saw the worst election result ever for the Union.[17] The CSU also had a weak showing with 5.2% of votes nationally and 31.7% of the total in Bavaria.

The CSU is the sister party of the Christian Democratic Union (CDU).[18] Together, they are called the Union.[18] The CSU operates only within Bavaria, and the CDU operates in all states other than Bavaria. While virtually independent,[19] at the federal level the parties form a common CDU/CSU faction. No Chancellor has ever come from the CSU, although Strauß and Edmund Stoiber were CDU/CSU candidates for Chancellor in the 1980 federal election and the 2002 federal election, respectively, which were both won by the Social Democratic Party of Germany (SPD). Below the federal level, the parties are entirely independent.[20]

Since its formation, the CSU has been more conservative than the CDU.[7] CSU and the state of Bavaria decided not to sign the Grundgesetz of the Federal Republic of Germany as they could not agree with the division of Germany into two states after World War II. Although Bavaria like all German states has a separate police and justice system (distinctive and non-federal), the CSU has actively participated in all political affairs of the German Parliament, the German government, the German Bundesrat, the parliamentary elections of the German President, the European Parliament and meetings with Mikhail Gorbachev in Russia.

Like the CDU, the CSU is pro-European, although some Eurosceptic tendencies were shown in the past.[21]

• List of Christian Social Union of Bavaria politicians
• Politics of Germany

• Alf Mintzel (1975). Die CSU. Anatomie einer konservativen Partei 1945–1972 (in German). Opladen. ISBN 9783531112787.

• Christlich-Soziale Union – official website (English page)
• Christian-Social Union (Bavaria, Germany)
• Christian-Social Union of Bavaria (CSU)