Correction: I say in the video that BND does the external spy control business of a normal secret service. It is actually also a duty of Verfassungsschutz. However, their focus is clearly on thought crimes.
The secret service Verfassungsschutz is a thought-crime-oriented intelligence agency which officially fights extremist thinking. It currently monitors the conservative party AfD as a “Prüffall”; that means based on publicly available information. It is expected that the party will be classified as a ‘Verdachtsfall’ in the coming week, which means that Verfassungsschutz can use secret spies and false identities to obtain information. It makes it also easier to get a warrant from a court to tap their post or telecommunication.
The party’s youth organisation ‘Junge Alternative’ is already a ‘Verdachtsfall.’ The patriotism caucus “Flügel” is even classified as a “Beobachtungsfall.” That means that warrants for intrusive measures are easier to obtain. At the end of this classification ladder a party can be banned as ‘hostile to the constitution.’ But that would require the consent of the Supreme Court and it is very unlikely to be the fate of the AfD anytime soon.
One criteria for such a ban based on ‘hostility against the constitution’ is ‘activities against the idea of an understanding between peoples’ (Art 9 GG (2)). In theory this means that a group or party can be banned if it objects to any foreign ideology and thus destroys the constitution-mandated Kumbaya. Even though a legal ban of the AfD is highly unlikely, an intensified monitoring creates propaganda fodder for people who see the AfD as hostile to the constitution because of their dislike of jihad.