The doctrine of the separation of powers is closely connected with the rule of law: the judiciary, by performing its constitutional function of 'enforcing' the law in the cases that come before it, keeps the executive within the bounds of its lawful authority and so upholds the law as made and sanctioned by Parliament. One of the key ways in which the judiciary performs this rule of law/separation of powers function is through the process of judicial review, which we will look at in detail in the final part of the course.