With the aim of barring Nicaragua’s fresh request for the delimitation of the continental shelf beyond 200 nautical miles, Colombia raised the issue of the res judicata effect of the previous decision of 2012, rendered in the Territorial and Maritime Dispute, whereby the icj had apparently settled the case and dismissed on the merits the same request. In the Judgment on preliminary objections of 2016, relating to the “new” case Question of the Delimitation of the Continental Shelf between Nicaragua and Colombia beyond 200 nautical miles from the Nicaraguan Coast, the icj held that no binding force attached to the operative part of the 2012 ruling. The outcome of the incidental proceedings was not predictable as one might have expected, given that the decision was taken with the casting vote of the President and prompted a strong dissent among some judges. This occurrence gives clear evidence of the interplay between several intertwined issues of international law, which the majority was called upon to deal with and balance in the present case, such as the interpretation of Article 76, paragraph 8 of the unclos, the principles of res judicata and jurisdiction ratione materiae and the duty to give reasons. The article aims to demonstrate that the Court dismissed Colombia’s third preliminary objection for underlying reasons of judicial policy, namely to secure its previous judgment of 2012 from any potential claim relating to inadequate reasoning, if construed as a final rejection on the merits.