While the United Nations brass failed to notice a direct Iranian threat of assassination against former American officials, it punished an Israeli diplomat on Tuesday for an apparent violation of decorum. 

Israel’s UN ambassador at the UN, Gilad Erdan, was temporarily detained by UN security after displaying on the General Assembly floor a poster of Mahsa Amini, a 22-year-old who was slain by Iranian forces a year ago, and whose death sparked national mass protest in Iran. Mr. Erdan carried the poster during a Tuesday speech by the Islamic Republic’s president. He then left the room in protest. Following a short-lived detention, Mr. Erdan was released. 

While in the past American officials left the General Assembly room when Iranian officials disparaged their country, a note taker remained there Tuesday as President Raisi contended that the abusive American world order is the past and the Islamic Republic is the future. The note taker didn’t seem to bat an eyelash as Mr. Raisi violated a much more consequential, though unwritten, diplomatic rule than Mr. Erdan did with his walkout: The Iranian president clearly threatened to assassinate officials of another state.

Mr. Raisi, known as the Tehran hangman, vowed to avenge the unnamed American “perpetrators” who were responsible for the 2020 killing of Qasem Soleimani, the arch terrorist. 

As commander of the Islamic Revolutionary Guards Corps’ Quds Force, and as Supreme Leader Khamenei’s closest confidant, Soleimani was charged with exporting the Iranian revolution to the region and beyond. For his role in sowing mass deaths in Syria, Yemen, Lebanon, Iraq, and elsewhere in the region, Soleimani topped America’s most wanted list until he was killed at the Baghdad airport by a U.S. drone. The Iranian regime turned him into a martyr. 

“Soleimani was the hero of anti-terrorism,” Mr. Raisi said in his Tuesday speech, vowing that the Islamic Republic “will not cease until justice is done” with the perpetrators responsible for Soleimani’s assassination. While very few statements from the UN podium have real consequences in the real world, this not-so-veiled threat was far from idle. 

In recent months the U.S. Secret Service has beefed up protection around Secretary Pompeo, a former national security adviser, John Bolton, a former Iran point man, Brian Hook, and other officials of the Trump administration who were involved in the decision to end Soleimani’s career as master terrorist. The extra security was reportedly added after credible intelligence was received on Iranian threats to assassinate the officials on American soil. The reason given was their role in the Soleimani killing. 

Similar assassination plots were also uncovered against exiled Iranian regime opponents who live in America. One such dissident, Masih Alinejad, was recently advised to join the witness protection program, as dozens of assaination plots against her by Tehran emissaries were uncovered. She declined to be silenced by disappearing into an oblivion normally reserved for mob informants. 

Mr. Raisi’s use of the UN’s gathering to publicly vow to avenge Soleimani’s death was a clear message that the IRGC and other Iranian-sent assassins will seek to kill Americans here at home, which is also where the UN headquarters is located. Under different circumstances such threats could land whoever issues them in prison. Yet, according to the host country agreement between the UN and America, the Turtle Bay headquarters environs are an extrajurisdictional zone, where U.S. laws don’t always apply. 

At the UN, in other words, a political stunt meant to protest grotesque injustice, such as Mr. Erdan’s walkout and display of the Amini poster, is punishable. An actionable threat on the lives of Americans who have already been subject to assassination attempts, in contrast, is merely part of a normal speech by a head of a member state.