In German politics, the 'firewall' (Brandmauer) is a long-standing informal agreement among mainstream parties, including the Christian Democratic Union (CDU), to refuse any form of cooperation or coalition building with the far-right Alternative for Germany (AfD). Recent scrutiny has focused on whether individual CDU lawmakers have breached this consensus at the local or state level.

While the national leadership of the CDU maintains a strict stance against working with the AfD, reports suggest that local political dynamics sometimes lead to informal voting alignments or cooperation on specific motions. Critics argue that any such interaction legitimizes the AfD, which is under surveillance by Germany’s domestic intelligence agency for suspected extremism. Conversely, some local officials argue that refusing to work with any AfD representative can lead to legislative gridlock on practical municipal issues.

The core of the controversy lies in the definition of 'support.' While some instances involve explicit voting together on local ordinances, others are accused of engaging in rhetoric that mirrors AfD talking points. The CDU leadership has faced pressure to clarify the consequences for members who bypass the firewall, with some officials calling for disciplinary action to maintain the party's ideological integrity. The situation remains fluid as the party attempts to balance local governance needs with its national commitment to isolating the far-right.