This Article discusses the constitutionality of the recently implemented § 89a IIa of the German Criminal Code (Strafgesetzbuch—StGB) on the basis of the case 3 StR 326/16 decided by the Federal Court of Justice (BGH) on April 6, 2017. First, this Article introduces § 89a IIa of the StGB with a short summary of the events leading to the present anti-terrorist legislation in Germany and the development of the legislation over the past few decades. Second, the facts of the BGH’s case will be outlined, and an overview of the systematic structure of § 89a I, II No. 1, IIa StGB will be provided. Within this framework, the constitutionality of § 89a IIa StGB will be discussed, focusing on the prerequisite of appropriateness, with special attention paid to the requirement of reasonability and the prerequisite of legal certainty pursuant to Article 103(II) Basic Law (Grundgesetz—GG). Finally, § 89a I, II No. 1, IIa StGB will be applied to the BGH’s case after discussing the contentious legal issues regarding these doctrines. This Article concludes by discussing the BGH’s decision, which deems § 89a IIa StGB to be constitutional.