After a warrant has been issued, the requested bulk SIGINT measure must be authorized or – as the case may be in different jurisdictions – approved by a review body that assesses the necessity and proportionality. Differences exist across nations as regards the moment when the independent judicial review process comes into play. In some countries, the competent minister or other members of the executive authorize warrants. In the United Kingdom, for example, the authorization of warrants is the privilege of the executive. Ministerial authorization, then, has to be approved by independent Judicial Commissioners. By contrast, in the German legal framework, warrants are authorized by bodies such as the G10 Commission or the Independent Control Council (for future foreign-foreign intelligence collection).
The independent ex-ante authorization/approval of data collection is a crucial safeguard against the misuse and abuse of bulk surveillance powers. The legitimacy of surveillance practice depends on the control of executive conduct from the outside. Enacting the control mechanism prior to implementation is crucial, because this can both deter and prevent certain actions from being taken. Independent authorization/approval also contains an important learning element, because the competent bodies can improve their controls, draw lessons from past mistakes, and then declare more assertively that certain measures are not required, or that no sufficient proof was presented.
Across many democracies, a dual system of authorization/approval has emerged that combines a judicial and an executive control function. A judicial oversight body – ideally a court – is best suited to administer a competent legal review of a bulk surveillance application.