In this and the following chapters, we examine how IIAs have featured as an argument in national lawmaking. Our focus has been primarily on the general legislative bodies with the power to issue laws applicable to the whole state, that is, national parliaments. We open the chapter with a discussion on the general parameters of the selected countries’ IIA-compliance review mechanisms in lawmaking. In the second part of the chapter, each state in our case studies is presented through a snapshot of an illustrative use of an IIA argument in lawmaking that is typical of that state’s experience with the IIA regime. As these snapshots are often related to contingent historical events and processes, we do not suggest that these uses are somehow essential to that state. Instead, they significantly overshadow the other instances of using an IIA argument in lawmaking in that state.