In 1688, the Bill of Rights stated that “debates or proceedings in Parliament ought not to be impeached or questioned in any Court or Place out of Parliament”. Since then, and for centuries, lawmaking process was far from the scrutiny of the judiciary. However, with the spread of constitutional courts after WWII, the so-called interna corporis acta doctrine started to limit its effects in the legislative process. The presentation examines case law of Chilean, Spanish, German and Colombian Constitutional Court and sheds light to new debates over the role of judges in the legislative arena and the right judicial scrutiny of law making due process. At the end, case law shows an active intervention of courts looking for the protection of several constitutional clauses or democratic values.