Germany’s domestic intelligence agency designated the right-wing Alternative für Deutschland party as “extremist,” shortly after it became the single most popular party in the country.

The Federal Office for the Protection of the Constitution, the Verfassungsschutz, justified its decision by claiming there were “numerous indications of efforts by the AfD to undermine the free democratic basic order,” indications that were “confirmed during further investigation.” The designation opens up the agency’s ability to surveil the populist anti-immigration party more thoroughly, among other legal consequences.