The International Court of Justice (ICJ) represents the principal judicial organ of the United Nations and functions as the world's highest court for resolving legal disputes exclusively between sovereign states. Understanding ICJ jurisdiction is crucial for CLAT aspirants because it sits at the intersection of international law, constitutional governance, and the system through which nations enforce their legal claims against one another. India, as a UN member state, is bound by the UN Charter and recognises the ICJ's authority within defined parameters. The ICJ's jurisdiction rests on three pillars: contentious jurisdiction (deciding disputes between states), advisory jurisdiction (offering non-binding legal opinions to UN organs and specialised agencies), and the principle of consent. No state is compelled to appear before the ICJ unless it has voluntarily accepted the court's jurisdiction through specific mechanisms: bilateral treaties, multilateral conventions containing dispute-resolution clauses, or declarations accepting the court's compulsory jurisdiction under the Optional Clause. This consent-based architecture reflects customary international law and the principle of sovereign equality enshrined in the UN Charter. India has made selective declarations accepting ICJ jurisdiction in certain matters but reserves the right in others—a posture adopted by most nations to protect sensitive national interests. The court's Statute, which forms Part III of the UN Charter, establishes these jurisdictional foundations, though the Statute itself does not appear as a scheduled instrument in Indian domestic law. Instead, India's participation flows from its constitutional commitment to international law and the UN Charter, which the Constitution recognises as binding. The interaction of these elements creates a precise legal architecture. Jurisdiction must exist ratione personae (both parties must be states and bound by consent), ratione materiae (the dispute must concern a legal question), and ratione temporis (the court's authority must have arisen before the dispute). When both conditions are satisfied, the ICJ issues binding judgments on the parties. However, this binding nature contains a critical caveat: enforcement depends entirely on the UN Security Council. If a state refuses to comply with an ICJ judgment, the winning party may petition the Security Council, which possesses authority to recommend or decide upon measures to give effect to the judgment, including sanctions or authorised military intervention. This distinction between binding force and enforceability is fundamental. A judgment may be legally authoritative yet practically unenforceable if the losing party—particularly a permanent Security Council member—blocks enforcement action. Advisory opinions, by contrast, carry persuasive but non-binding weight; they guide interpretation but do not create legal obligations. The court cannot compel participation; it cannot override state sovereignty; and it cannot enforce its own orders without institutional backing. These limitations distinguish the ICJ sharply from domestic courts and explain why states sometimes comply with adverse judgments through political or reputational pressure rather than external coercion. The ICJ occupies a unique position within both international law and India's constitutional framework. The Constitution recognises India's duty to respect international law and protect international peace—values reflected in the Preamble and the Directive Principles of State Policy. While the Constitution does not grant domestic Indian courts power to enforce ICJ judgments directly, Parliament could legislate to incorporate such judgments into Indian law if India were a party. The ICJ operates alongside other dispute-resolution mechanisms—bilateral negotiation, arbitration, regional courts, and treaty-based tribunals—but retains primacy as the UN's principal legal forum. It differs fundamentally from the Security Council, which exercises political discretion, and from the General Assembly, which lacks binding judicial power. The concept of state immunity, the act of state doctrine, and principles of non-interference are neighbouring doctrines that shape ICJ jurisdiction; a state cannot be sued without consent, and the court respects the political branches' authority over matters of national security or sovereignty. CLAT examiners frequently distort this principle in several characteristic ways. First, they present fact patterns where a non-state actor (a corporation, an NGO, or an individual) attempts to sue in the ICJ, then ask whether the court has jurisdiction—the answer is always no, but candidates often conflate ICJ rules with domestic court rules permitting broad standing. Second, examiners reverse the consent requirement by implying that one state's unilateral declaration can bind another state that has not consented—this contradicts the bilateral nature of contentious jurisdiction. Third, they confuse advisory opinions (non-binding guidance) with contentious judgments (binding decisions), presenting scenarios where an advisory opinion is treated as enforceable. Fourth, they omit the Security Council element entirely and ask whether a judgment is automatically enforceable—candidates must remember that enforcement is a separate institutional question. Fifth, they import doctrines from domestic constitutional law (such as separation of powers or due process) and ask whether these limit ICJ jurisdiction, when in fact international law and consent are the governing criteria. Sixth, they present India-specific twists: asking whether India can be sued in the ICJ without its consent (no), or whether an ICJ judgment automatically overrides an Indian statute (no, unless Parliament legislates incorporation). Finally, examiners sometimes blur the distinction between the ICJ and other UN bodies, asking about the General Assembly's or Security Council's 'judicial' powers, which do not exist in the ICJ sense.