Operation Rising Lion: When diplomacy breaks, deterrence speaks

Diplomacy is vital, but when rules are broken and threats ignored, deterrence becomes essential.

On June 13, 2025, the world woke up to the roar of jet engines over Iran. "Operation Rising Lion" was not merely a military maneuver—it was an act of deterrence, a line in the sand drawn by a country whose very existence is under constant threat. Israel’s precision strikes on Iran's nuclear facilities in Natanz, Isfahan, and Fordow, alongside IRGC missile infrastructure, were the answer to a question the international community had long been too timid to face: what do you do when diplomacy fails, and your adversary is sprinting towards a nuke?

As someone who teaches diplomacy and believes deeply in its power, I do not ask this question lightly. Diplomacy is the tool of the civilized world. But even those of us who defend dialogue and treaties must confront moments when the rules are broken, the treaties ignored, and the consequences of inaction become too great.

Preemption is not provocation

In 1842, American diplomat Daniel Webster articulated what became known as the Caroline Test—a principle of self-defense that still stands. It permits a state to strike first when a threat is “instant, overwhelming, and leaving no choice of means, and no moment for deliberation.”

That’s precisely where Israel stood on June 12, when the IAEA reported Iran was non-compliant with the NPT for the first time in two decades. Iran’s breakout time for a nuclear weapon had narrowed to just one week. The threat was real, immediate, and confirmed.

The world has seen moments like this before. During the Cuban Missile Crisis in 1962, the United States imposed a naval blockade on Cuba to prevent the deployment of Soviet nuclear missiles. It wasn’t an act of aggression—it was a necessary measure to stop an existential threat. In 1981, Israel bombed Iraq’s Osirak reactor; while condemned at first, that operation was later credited with halting Saddam Hussein’s nuclear ambitions. In 1991, U.S.-led forces eliminated Iraq’s nuclear facilities during the Gulf War—again, preemptively. And more recently, the international coalition’s intervention against ISIS demonstrated that when a regime or group poses an imminent, transnational threat—especially with genocidal intent—military action becomes the only responsible choice. The Islamic State was not negotiated with; it was dismantled.

Preemption is a grim choice, one no nation makes lightly. Israel’s leaders knew the strikes could spark retaliation or global criticism. But with Iran’s nuclear clock ticking, the risk of waiting was far greater.

When safeguards fail

The 2015 Joint Comprehensive Plan of Action (JCPOA) was designed to constrain Iran’s nuclear capabilities through inspections and limits on enrichment. But by 2023, Iran had surpassed all constraints. By 2025, it had expelled inspectors, expanded its stockpile, and installed advanced centrifuges. The mechanisms intended to stop this breakdown—including "snapback" sanctions—were never triggered.

The snapback mechanism, a built-in safeguard of the JCPOA, allowed any signatory to unilaterally reimpose UN sanctions if Iran was found in material breach of the deal. Its purpose was to deter violations by ensuring automatic consequences. Yet, despite mounting evidence and formal IAEA warnings, no party activated it. The system existed on paper but failed in practice.

European powers, especially the E3 (France, Germany, UK), possessed both the legal basis and political influence to enforce the deal. But faced with a shifting global order and internal divisions, they hesitated. Statements were issued. Concerns were raised. But no penalties followed.

This is not to say European leaders were complicit. The paralysis stemmed from systemic challenges: competing political priorities, diplomatic fatigue, and an international climate where collective action often lags behind the pace of crisis. Still, the effect was the same. The deterrent power of diplomacy eroded.

The stakes extend beyond Israel

Iran’s threats towards Israel have never been rhetorical. Supreme Leader Khamenei has referred to Israel as a "cancerous tumor," and public clocks in Tehran count down to its "destruction." A few days ago missiles launched towards Tel Aviv and Haifa killed civilians and injured hundreds. These are not abstract declarations. They are policy, implemented with deadly intent.

According to official state doctrine, the annihilation of Israel is the regime’s primary foreign policy goal. But as Mathias Döpfner warns, “Israel is only the first target. Once Israel falls, Europe and America will be the focus.” Iran’s ambitions are not regional—they are civilizational.

In 2012, Iranian-backed Hezbollah carried out a bombing in Burgas, Bulgaria. In 2020, Germany banned Hezbollah-linked groups after uncovering terrorist plots. Analysts warn that deepening Iran-Russia ties could turn missile and nuclear technologies into tools of regional or even continental coercion. A nuclear Iran would not be a local problem. It would be a strategic crisis for the entire West.

Not all nuclear powers are the same

Critics often ask: why is Israel allowed nuclear weapons while Iran is not? The difference lies in conduct, not capability.

Israel has never threatened to annihilate another country. It has never used its nuclear ambiguity as a tool of aggression. Iran, on the other hand, has openly promised destruction, finances terrorism as statecraft, and is actively violating international agreements.

Iran already funds terrorism to the tune of $1 billion per year (at least), supporting Hezbollah, Hamas, and the Houthis. These groups have attacked civilians across the Middle East and beyond. A nuclear-armed Iran would give these proxies impunity—backed by a regime shielded from retaliation.

Israel is not a signatory to the NPT. Iran is—and has violated its terms repeatedly.

This was deterrence, not revenge

Israel's operation was precise. It targeted nuclear sites and missile infrastructure while sparing civilian centers. Its message was not one of vengeance, but of red lines: that nuclear weapons in the hands of a regime committed to regional domination and ideological warfare would not be tolerated.

The risks of escalation are real: retaliation from Hezbollah or the Houthis, oil market disruptions, diplomatic friction. But the cost of passivity is far greater. A nuclear-armed Iran would embolden proxy warfare, provoke an arms race across the region, and further destabilize the global order.

A transatlantic imperative

Europe cannot afford to watch from the sidelines. The Iranian threat is not hypothetical. It is historical, active, and evolving. Whether through terror attacks, nuclear proliferation, or strategic alliances that circumvent Western norms, Iran has demonstrated its reach.

A united Western response is not just an act of solidarity with Israel. It is a form of self-preservation. Preserving the rules-based order requires more than statements of concern. It requires credibility.

Diplomacy’s breaking point

Diplomacy must always be our first resort. I teach it because I believe in it. But diplomacy has an edge—it works only when backed by strength and consequences.

Israel’s operation was not the failure of diplomacy. It was diplomacy’s last line of defense. It reminded the world that freedom, if it is to mean anything, must sometimes be protected by force.

If the free world wants to remain free, it must not punish those who act when it cannot. It must understand that the time for words had passed—and that silence, too, is a kind of decision.