The most important goal of German police law is to avert threats to public safety and order. The concept of danger has a long tradition in German police law. The Prussian Police Administration Act of 1931 already stipulated that the police could only intervene in the rights of citizens if there was a "danger". Danger was understood to mean a situation which, if it continued unhindered, would give rise to serious fears of damage. According to the case law of the Prussian Higher Administrative Court, the danger did not have to be imminent. However, the occurrence of the damage had to be at least as probable as its absence. The federal states after 1949, which in the Federal Republic have the legislative competence for general police law, also oriented themselves on this model. In principle, encroachments on fundamental rights are only permissible if there is a danger. The mere assumption that a situation is dangerous is not sufficient.

In response to new threats, this classic constitutional concept of police law has been further developed in recent decades. This change was triggered by the terror of the "Red Army Faction", which carried out numerous attacks on politicians and public institutions in the 1970s and 1980s. Other impulses for the further development of police law came from the fight against so-called "organized crime", i.e. organized drug trafficking, but also human trafficking. The attacks of 11.9.2001 and Islamist terror marked a central turning point. New police powers have been created in Germany, as in many other countries, to ward them off.

These new police powers allow the police authorities to secretly interfere with fundamental rights in order to clarify a dangerous situation. In contrast to traditional measures, the police can therefore take action in the run-up to a danger. To this end, there must be sufficient factual indications of a danger situation. Examples include the use of covert investigators, directional microphones or telecommunications surveillance.

A reform of Bavarian police law in July 2017 goes one step further. It is now also permitted to intervene in the causal process, which can be based on an extended general clause in the event of imminent danger. The article discusses the objections raised against the new powers. Violations of the principle of certainty and the principle of proportionality are criticized. This criticism is only partially convincing. The concept of imminent danger goes back to the case-law of the Federal Constitutional Court. If the facts of the imminent danger are interpreted very narrowly in accordance with the constitution, they are likely to correspond both to the requirement of certainty and to the principle of proportionality. The criticism of interventions in the causal process is not convincing. These are open measures, so that the Administrative Procedure Act applies. This means that it is necessary to hear the parties concerned, who can defend themselves against the suspicion. This also has consequences for the principle of certainty, which can be lowered in its requirements in the case of open measures. However, it has not been regulated against whom the measures are to be directed. The legislator should clarify the law here.