People in traditional costume take part in the “Gaufest” parade in Murnau, Germany, on July 8. (Michaela Rehlen/Reuters)

Philipp Liesenhoff is an associate fellow at the German Council on Foreign Relations’ Globalization and World Economy Program and an AICGS/GMF fellow with the American-German Situation Room in Washington.

When most Americans think about Germany, they really think about Bavaria. Lederhosen, beer, pretzels, beautiful mountain landscapes and the Disney-esque castle Neuschwanstein have little to do with any of the other 15 German states. But Bavaria’s culture is not only an external marketing success. Its political tribalism has evolved into a serious threat for German politics and European unity. In an unprecedented escalation over Germany’s migration policy, Chancellor Angela Merkel’s exclusively Bavarian sister party, the Christian Social Union (CSU), is undermining a European solution and has destabilized the government. For Germany, it would be best if Merkel’s Christian Democratic Union (CDU) and the CSU separated.

Merkel faces the most dangerous political threat in her nearly 13 years as chancellor. The CSU is running a far-right populist campaign against her liberal migration policy out of fear of losing more voters to the right-wing Alliance for Germany (AfD) in state elections in October. This has culminated in a showdown between the chancellor and the interior minister and CSU leader, Horst Seehofer. Merkel blinked to save her government from a breakup and reluctantly agreed to stricter immigration controls — but it has not been enough.

The CSU is keeping the pressure on Merkel. Seehofer wants an “asylum turnaround” by nationally limiting migrant inflows — a goal he shares with the radical right-wing interior ministers of Austria and Italy. In a meeting of European Union interior ministers set for this week, Seehofer will discuss closing the Mediterranean route, which will likely deflect migrant flows to Spain and Greece and could trigger a nationalist chain reaction and the end of European migration policy. Bavaria has become a better ally to the right-wing Italian League and the Austrian Freedomy Party than to Merkel’s CDU.

Bavarian politics has contributed significantly to the introspective and provincial scope of German politics in recent years. The CSU’s latest stunt is part of a long line of affronts against German chancellors to elevate the party’s regional conservative profile. Seehofer is supported by the current Bavarian governor, Markus Söder, who has been labeled a “bonsai Trump.” Their political priorities under “Bavaria First” follow a long CSU tradition. Former Bavarian governor Franz Josef Strauss (CSU) once famously said: “I don’t care who becomes German chancellor below me”. The state’ political and cultural self-perception is as celebrated by Bavarians as it is bewildering to the rest of Germany.

The CDU-CSU arrangement means that if you’re voting in Bavaria and you want the CDU to win the national elections, you have to vote CSU. The CSU’s agenda is more xenophobic, fiscally conservative and socially regressive — nothing you necessarily want to vote for if you think Merkel’s rational moderation rather than erratic barking is the right way to steer a country.

And then there is the CSU’s constant flirtation with illiberal forces in Europe, such as the alpine anti-immigration allegiance with Austria and Italy, in which Bavaria counteracts Berlin’s very different positions while actually not having any foreign policy competence.

Bavarians have been lulled into the belief of Bavarian exceptionalism. It isn’t rare to hear strangely North Korean-sounding things like “the sun will shine for most of the day in our blue and white Bavarian sky” — hinting at the blue and white Bavarian flag — “and will illuminate the grand landscapes of our beautiful state.” There is also a secessionist current that runs deep in Bavaria. According to a poll from the German newspaper Bild conducted last year, over 30 percent of Bavarians would support the state’s independence.

Until now, Bavarian tribalism had largely been tolerated in Berlin as a hated but needed factor to secure power for Christian Democrats. However, the provincial theatrics and political derailments of the CSU are becoming increasingly counterproductive at a time when Germany must assume more leadership responsibility on the world stage. Germany just can’t afford this toxic political union anymore.

Read more:

Karen Attiah: Germany’s ‘homeland’ propaganda is making an inglorious return

Christian Caryl: Is Germany’s grand coalition the beginning of the end for Angela Merkel?

Letters to the Editor: Merkel remains an essential presence in a free Europe

Judy Dempsey: Angela Merkel is becoming Europe’s weakest link

Josef Joffe: The greatest miscalculation of Angela Merkel’s career