In the last decades, there has been an increase in advisory opinions of the International Court of Justice (ICJ) that relate to vital political interests directly affecting the sovereignty of states. Even though advisory opinions are not binding and do not require the consent of the states involved, advisory proceedings have been increasingly and strategically used by states and international actors as contentious proceedings in disguise. Exploring the history of the advisory function of the ICJ and its predecessor, this article argues that advisory proceedings constitute a "soft" litigation strategy and a particularly useful tool for small states or non-state entities, as it has the potential to counterbalance the inherent power disparities in the process of international bargaining by adding the authoritative voice of the ICJ to the debate. This paper connects this development to a modern tendency of states to judicialize international affairs.