ed to limit the authorised means of surveillance to the technological state of the art
at the point in time of the legislative process. As long as the type of surveillance that
is permitted can be sufficiently made out, the legislature can provide that the authorisation shall also cover future technological developments. […] Furthermore, it falls
upon the legislature to carefully observe technological developments and to take appropriate corrective action if the specific defining of openly phrased legal terms takes
an undesirable turn (cf. BVerfGE 112, 304 <316 and 317>).
d) § 20g sec. 1 no. 2 BKAG, however, is not compatible with the constitutional requirements. The conditions for interference neither satisfy the principle of specificity
nor the principle of proportionality in the narrow sense.
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aa) § 20g sec. 1 no. 2 BKAG complements the basis for interference of § 20g sec. 1
no. 1 BKAG, which is limited to the protection against threats. It is intended by the legislature to set in earlier and serve to prevent criminal offences.
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According to the standards set out above, the legislature is not generally prevented
nor constitutionally barred from limiting security measures to the protection against –
according to established understanding – specific threats. However, even in respect
of measures for preventing criminal offences, a prognosis is needed that is based on
facts relating to a specific threat, rather than merely on general experience. In principle, this means that an occurrence that is specific at least with regard to its type, and
temporally foreseeable, must be in evidence (cf. BVerfGE 110, 33 <56 and 57, 61>;
113, 348 <377 and 378>; 120, 274 <328 and 329>; 125, 260 <330>). In respect of
terrorist offences, the legislature can alternatively also apply the standard of whether
the individual behaviour of a person substantiates the specific probability that the person will commit a terrorist offence in the near future (see above, C IV 1 b). The requirements to this effect must be set out with legal clarity.
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bb) § 20g sec. 1 no. 2 BKAG does not satisfy these standards. The provision does
indeed require the possible commission of a terrorist offence. Yet the prognosis requirements to this effect are not sufficiently substantive. The provision does not preclude the possibility that the prognosis is solely based on general experience. It neither contains the requirement that an occurrence that is specific at least with regard to
its type and temporally foreseeable must be in evidence, nor the alternative that the
individual behaviour of a person must substantiate the specific probability that the
person will commit a terrorist offence in the near future. Thus, the provision does not
give the authorities and the courts sufficiently specific criteria to work with and provides for measures that can be disproportionately broad.
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e) If interpreted in conformity with the Constitution, there can, in contrast, be no constitutional objection to § 20g sec. 1 no. 3 in conjunction with § 20b sec. 2 no. 2 BKAG.
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§ 20g sec. 1 no. 3 BKAG also allows measures affecting contacts or accompanying
persons. The term “contacts or accompanying persons” is defined in greater detail in
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