When President Biden arrives in Lithuania for this week’s NATO summit, critics no doubt will rebuke his decision to transfer “banned” cluster munitions to Ukraine. Yet any criticism will pale in comparison to the universal fury at Israel’s use of that weapon in 2006.

The war then between Israel and Hezbollah led 111 countries to sign the 2008 Convention of Cluster Munition to ban the use of the weapon and its export. The treaty, conceived at Oslo, is fueling current American and international critique of Mr. Biden’s decision — even though America and Ukraine are not members of the convention. Another non-member, Russia, has been using such bombs throughout the war. 

Cluster munitions, which break into hundreds of bomblets, have been used in battle since the Vietnam war to hit areas wider than other artillery or aerial-dropped bombs. Critics have long zeroed in on the weapon’s high rate of unexploded munitions, or duds, which pose dangers to civilians, including children, well after wars end. 

While human rights groups have long raised such concerns, the push for banning the munitions gained crucial speed following the 2006 war, in which Hezbollah shelled Israeli cities daily from missile launchers placed inside villages and towns in southern Lebanon. 

The Israel Defense Forces’ use of cluster bombs to neutralize the threat led to criticism at the United Nations and in Congress. Unlike when NATO employed cluster bombs against Serbia a few years earlier, or when the allies used those arms in Iraq and Afghanistan, the IDF was widely accused of violating the rules of war. 

“The use of cluster munitions by anyone, anywhere in the world, in my view, is immoral,” the UN undersecretary general for humanitarian affairs, Jan Egeland of Norway, told the Security Council weeks after the end of the Lebanon war. He urged the council “to support a moratorium on the use of cluster munitions, a weapon which belongs in the garbage cans of history.”

Israel’s Winograd commission that investigated the IDF’s conduct in the war criticized the army command’s lack of clarity on when and where cluster bombs would be used. Yet, the IDF’s top legal official, Avichai Mandelblitt, ruled that the army was acting according to the rules of war relating to proportionality. 

According to that principle, Hezbollah’s missile launchers became a legitimate military target even while incidental deaths of some civilians were involved in their destruction. As even the UN secretary-general, Kofi Annan, said at the time, launching missiles from civilian centers is a war crime.

Yet, Annan was quick to leverage the widespread anger at Israel to push a convention to universally ban cluster munitions. The Lebanon war shows “the atrocious, inhumane effects of these weapons,” he told a gathering at Geneva. “I call on you to freeze the use of cluster munitions against military assets located in or near populated areas.”

So, an international convention was born. Additionally, Israel’s use of American-made cluster munitions led some in Congress to call for limits on all arms deliveries to the IDF. “This is a legitimate issue to consider, and, perhaps, to legislate,” the head of the Senate Foreign Relations Committee at the time, Senator Biden, said, adding that “it should be done in a careful manner, after holding hearings and with proper preparation.”

Mr. Biden’s current critics highlight that statement, as well as one by the American UN ambassador, Linda Thomas Greenfield, who recently said that Russia’s use of cluster bombs in Ukraine could amount to a war crime. Yet, Ukraine’s case may be different from past debates over cluster munitions.

America’s current cluster munitions are much less likely to leave behind many unexploded particles. Their dud rate, according to the Pentagon, is below 2 percent. They are therefore less harmful to civilians than weapons that were used in Serbia, Lebanon, or Iraq, or the ones Russia is using in Ukraine, which on average leave 40 percent unexploded droplets. 

Additionally, Ukraine will use the weapon in its own occupied territory. It’s up to Kyiv, not anyone else, to decide whether possible post-war danger to Ukrainian civilians is a risk it is willing to take to end the Russian occupation. 

Also, while Norway, Canada, New Zealand, and other members of the cluster munition convention criticize Mr. Biden’s decision, their protest is far less ferocious than the all-out attack on Israel in 2006. It is unlikely, for one, to lead to a deeply divided NATO at its Vilnius summit. 

Mr. Biden discussed his decision at London on Monday with one critic of cluster munition use, Prime Minister Sunak. As Sky News aptly paraphrases that critique, it amounts to: “We’d rather they were not on the battlefield, but we recognise their necessity, we note their low dud rate, and we need to see Putin fail.”

The cluster munition is a useful weapon of war that can help the Ukrainian army defeat a well-dug-in Russian force. Countries that never fathom fighting wars tend to frown on almost any weapon that kills. Those who do fight wars face a much more complex decision-making process.