If I may add to that, when courts or tribunals review decisions that are made by the executive and that have a policy component, they typically show deference, in the sense that they do exercise some form of control but they recognize that the executive has a margin of discretion.
They typically ask themselves if the executive decision was reasonable. They don't ask themselves what decision they would have made had they been in the Prime Minister's shoes or the ADM's shoes. Rather, they look at reasonableness. It's the same thing for security certificates, for example. This is a standard of a review that has proven practicable and that does not intrude too much on the kind of discretion that is necessary when matters of national security are at stake.