The tariffs on steel and aluminium products imposed by the United States under the pretext of national security presented an unprecedented challenge to the functionality of the current multilateral trade governance system based on the WTO agreements. The ambiguity in the interpretation of the security exceptions contained in the GATT, GATS, and TRIPS left ample room for speculation as to the legitimacy of these trade-restrictive measures under international trade law. This delicate balance has been shaken by the recent WTO panel report in Russia – Measures concerning traffic in transit case, which provided a long awaited guidance on the interpretation of Article XXI GATT. The paper provides an analysis of the security exceptions in WTO law following the debate on their interpretation and application in the recent cases including the U.S. tariffs, the EU/U.S.-Russia confrontation over Ukraine and Gulf States’ embargo against Qatar.