BERLIN—Germany’s government has withstood an assault from within, but the process revealed a ruling coalition increasingly beholden to the growing nationalist tendencies of its smallest member. The Christian Social Union, or CSU, operates only in the southeastern state of Bavaria, on Germany’s border with Austria. But in an unusual arrangement dating back to 1949, it has been the sister party of the Christian Democratic Union, or CDU, which competes in the country’s 15 other states and which Chancellor Angela Merkel has led since 2000.
Although the CSU holds the fewest seats of any party in the Bundestag, Germany’s national parliament, those seats are critical to the CDU’s majority coalition, which also includes the country’s second-largest political party, the center-left Social Democrats, or SPD.
This leaves the CSU, and its conservative, Bavaria-centered worldview, with outsized influence over national politics. At the center of that worldview are concerns over immigration and a desire to sharply restrict any future arrivals to Germany. Those concerns are becoming increasingly acute ahead of local Bavarian elections in October, in which the CSU fears it will lose significant votes to the far-right Alternative for Germany party, with its even harder-line, anti-immigrant platform.