(see above, C IV 3 c bb, d). Such provisions are lacking, so that § 20g secs. 1 and 2
BKAG are not compatible with the Constitution in that respect either.
2. § 20h BKAG, too, only partially satisfies constitutional requirements.
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a) § 20h BKAG permits audio and visual surveillance in private homes. It thus constitutes an interference with Art. 13 sec. 1 GG.
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With the power to conduct surveillance within private homes, the provision authorises interferences with fundamental rights that are particularly serious. It permits the
state to penetrate into spaces that are a person’s private refuge and that are closely
linked to human dignity (cf. BVerfGE 109, 279 <313 and 314>). This does not, as implied by Art. 13 secs. 3 and 4 GG, rule out surveillance measures. The protection
against threats from international terrorism may justify such measures (see above, C
II 3 a). These are, however, subject to particularly strict requirements, which § 20h
BKAG does not fulfil in every respect.
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b) § 20h secs. 1 and 2 BKAG is not constitutionally objectionable insofar as it – comprehensively, with regard to all persons potentially addressed – governs the general
conditions for the surveillance of private homes.
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aa) The provision does satisfy constitutional requirements insofar as it limits measures to the protection of particularly weighty legal interests, and at the same time requires the presence of imminent danger, and defines the persons addressed by it as
those responsible for particular actions or circumstances.
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[…]
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bb) In accordance with Art. 13 sec. 4 GG, the provision also requires the presence
of imminent danger. For this, both the extent as well as the probability of the damage
to be expected must be considered (cf. BVerfGE 130, 1 <32>). Strict requirements,
going beyond those needed in relation to a specific threat, must be laid down with regard to the presence of imminent danger (cf. BVerwGE 47, 31 <40>; Decisions of the
Federal Court of Justice in Criminal Matters – Entscheidungen des Bundesgerichtshofs in Strafsachen – BGHSt 54, 69 <83 and 84>). From a proportionality perspective, this does ensure sufficiently specific grounds for carrying out such measures
(see above, C IV 1 b).
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cc) The provision is also not disproportionate for permitting audio as well as visual
surveillance of private homes. The fact that the Constitution does not already fundamentally rule out visual surveillance of private homes for interferences serving to protect against threats pursuant to Art. 13 sec. 4 GG can be deduced a contrario from
Art. 13 sec. 3 GG. However, interference combining audio and visual surveillance
carries substantially more weight than, for example, audio surveillance only, and requires special justification. Accordingly, when ordering these measures, the suitability, necessity and appropriateness requirements for each form of surveillance must be
examined individually, as well as with a view to their combination with one another,
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