The U.N. Security Council convened an emergency session last week to review Israel’s ongoing military attack targeting Iran’s nuclear-weapon facilities and related leaders. Israel’s traditional U.N. adversaries said it committed an unprovoked breach of international law. In actuality, Israel’s actions constitute justifiable self-defense under two lines of international law.
U.N. Charter Article 51 and customary international law give states the right to use military force in two situations: self-defense against an actual armed attack and “anticipatory self-defense” against an imminent armed attack.
Assessing Israel’s military operation requires a look at both legal rights.
Through a decades-old alliance of jihadist terror groups called the “Axis of Resistance,” Iran has been orchestrating a campaign of armed attacks on Israel. The axis members serve as Iran’s proxies and pursue Tehran’s well-publicized strategic goal to destroy Israel, and ultimately, to replace Western civilization with Islamic rule. To that end, these terror proxies have been striking Israel under an umbrella of Iranian funding, weapon smuggling, military training and intelligence sharing. Iranian leaders promote the cause with chants of “Death to America, Death to Israel.”
The Iranian-sponsored aggression ignited a full-scale war on Oct. 7, 2023, with the Hamas-led terrorist attacks in southern Israel. During and after the slaughter and atrocities, Israel came under attack from multiple directions: Hamas and Palestinian Islamic Jihad in Gaza; Hezbollah, an Iranian proxy, in Lebanon; terrorist militias in Syria; Houthi rebels in Yemen; Shi’ite militias in Iraq; and Palestinian terror cells in Judea and Samaria. Iran itself fired two waves of missiles and drones at Israel in 2024.
Legally speaking, Iran’s “substantial involvement” in the proxy war against Israel permits the Jewish state to launch counteroffensives against Iran and its proxies, based on a 1986 ruling of the International Court of Justice in The Hague. In short, the collective war against Israel justifies Israel’s strike on Iran as an act of self-defense.
Israel’s actions are also justified by the international law right of anticipatory self-defense. The classic example of anticipatory self-defense was the 1967 Six-Day War, when Israel pre-empted an imminent armed attack by Syria, Egypt and Jordan. Israel took similar steps when it pre-emptively bombed the Osirak Iraqi nuclear reactor in 1981, as well as when it pre-emptively hit a Syrian nuclear reactor in 2007.
The concept of an imminent armed attack is not explicitly defined. But in 2012, the United States and other democracies interpreted the term by devising the Bethlehem Principles. Applying those criteria to the Iran-Israel showdown reveals there was ample evidence as of June 13, or earlier, that an Iranian nuclear attack on Israel was imminent.
The first criterion examines the “nature and immediacy of the threat,” disregarding whether the defending state knows the exact time, place and means of attack. The U.N. International Atomic Energy Agency discovered Iran’s undeclared nuclear enrichment activities and announced, in 2003, the regime’s violation of the Nuclear Non-Proliferation Treaty. Subsequently, the United Nations engaged Iran in protracted diplomacy to cure the noncompliance, but Iran deceptively continued its nuclear progress.
The IAEA said on June 12 that Iran breached its nuclear obligations, having enriched so much uranium to near-weapons grade purity that it could produce several nuclear bombs. Israeli intelligence predicted that a nuclear weapon could be made within weeks. That fact, in light of Iran’s anti-Israel proxy war, confronted Israel with an immediate existential threat.
The next Bethlehem criterion studies whether any third parties support the anticipated aggressor. In this case, the third-party support comes from Iran’s Axis of Resistance.
The analysis also asks whether the anticipated attack is part of “a pattern of continuing armed activity.” In this case, the proxy war on Israel has convulsed the region for 20 months.
Another factor estimates the scale of potential damage from an anticipated attack. A single Iranian nuclear missile detonated over a tiny country like Israel could not only destroy it but complete an antisemitic genocide greater than the Holocaust.
Finally, the Bethlehem inquiry considers any attempts to pursue defensive alternatives, ones less drastic than the use of military force. Many attempts were made to restrain Iran nonviolently. Most significant among them was a nuclear limitation agreement, the 2015 nuclear deal titled the Joint Comprehensive Plan of Action, which was signed by Iran and six world powers in 2015. The contract was structured to delay, but not stop, Iran from producing nuclear weapons, and, therefore, the United States withdrew from the arrangement in 2018.
Earlier this year, the United States offered Iran a 60-day period in which to negotiate a new nuclear limitation deal. Unfortunately, the U.S.-Iranian talks reached an impasse. Iran faced economic sanctions from the U.N. Security Council, the European Union, the United States and other major democracies. None of these peaceful measures convinced the fundamentalist regime to stop its nuclear enrichment. Israel waited out the 60 days before taking action.
For decades, Iran’s leaders have obsessively vowed to eliminate the “Zionist entity.” But as the Bethlehem Principles recognize, a nation need not stand still as its enemy prepares to attack, especially when the attack threatens nuclear annihilation.
Israel’s attack on Iran flows from two rights of self-defense: one to repel actual attacks from the Axis of Resistance and the other to defuse an anticipated nuclear attack from Iran. Neither of these lawful imperatives satisfies Israel’s opponents. It’s a familiar story. Everyone recognizes the right of self-defense … until Israel invokes it.