Efficient but controversial: the most important questions about cluster munitions for Ukraine Sanda Dia died during a brutal admission rite – his story is on the minds of all of Belgium

How do cluster munitions work?

The principle of cluster munitions is simple: imagine a container containing many small bombs. The container opens in the air and scatters the sub-munitions, called “bomblets”, over the target. The result: widespread bombardment.

These “containers” come in various forms: as bombs (cluster bombs), as artillery shells fired from howitzers (canister ammunition), or as nuclear warheads from ballistic cruise missiles. In international technical jargon, cluster munitions are also referred to as “cluster munitions”, and bombs as “CBUs” (Cluster Bomb Units).

The bombs also come in different forms: some are incendiary, some are armor-piercing, and some stick in the ground like landmines.

The idea of ​​cluster munitions is not new. A so-called “rain ball” can be found in the fireworks book published in 1682 by the Prussian artillery captain Ernst Braun. These wooden cartridges contained hand grenades that were ejected across the battlefield and simultaneously ignited by a pre-launched retarding charge.

During World War II, all major warring factions used various types of cluster munitions. During the Winter War (1939/1940), early Soviet cluster bombs became known in Finland as “Molotov’s granary”.

After the Second World War, the US and the Soviet Union in particular were involved in the further development of cluster munitions. This was therefore also (again) developed as artillery ammunition. With the “15.5 mm KaG 88”, the Swiss artillery also adopted a variant of the so-called canister ammunition.

Switzerland also bought conventional aircraft-dropped cluster bombs: in 1980, Parliament approved the purchase of 2,000 British BL755 cluster bombs. The cost was about 90 million Swiss francs.

Today, cluster munitions are one of the most widely used anti-aircraft weapons. It is often used in a combination of high-explosive, fragmenting, and armor-piercing bombs.

Why is cluster munitions controversial?

Cluster munitions are useful as long as they work. A 2006 report states that, according to demining personnel, 10 to 30 percent of bombs fail to detonate after impact and remain on the ground.

There are a few factors that determine whether a bomb will explode. If the ground is too soft, for example after heavy rainfall, the detonator will not go off. Bushes and trees can slow down the speed of the bombs enough that they don’t explode. Or they just land upside down so that the detonator registers no impact.

The problem with this is that the submunitions remain active. Mishandling these duds can be deadly, Amnesty International’s weapons expert Brian Castner told the New York Times: “To touch this thing wrong is like lighting a match.”

A report by the International Red Cross summarizes the effects of the use of cluster munitions in the Kosovo war. Such cluster bombs were therefore responsible for 102 deaths or injuries in the first year after the war. In contrast to the victims of ordinary anti-personnel mines, the victims of bombs were on average significantly younger.

The reason for this lies in the shape of the submunition: depending on the version, the fist-sized, round bombs are reminiscent of Easter eggs or something similar. Curious children like to read something like this – and in the worst case, set off the detonator.

Why do some states use cluster munitions and others don’t?

“There’s just no responsible way to use cluster munitions,” said my Amnesty expert Castner. That was also the conclusion of 107 countries in 2008 when they agreed to the treaty on the abolition of cluster munitions at a conference in Dublin.

Incidentally, the first signatory to this treaty was NATO Secretary General Jens Stoltenberg, the then Prime Minister of Norway. Switzerland, represented by EDA boss Micheline Calmy-Rey, signed on December 3. Army officers protested at the time. The Swiss army has now destroyed all canister munitions and cluster bombs in its possession.

But this treaty does not mean the end of efficient but dangerous ammunition. Because by no means all countries have signed the treaty. A look at the map of the signatories shows that certain geopolitically relevant states have no interest in banning cluster munitions:

Not participants include Russia, the United States and Ukraine.

Why does Ukraine want cluster munitions?

The conditions for Ukraine to be able to use American cluster munitions are therefore in place. But do Ukraine’s many small CBUs really give them an advantage in their offensive?

Yes. At least that’s what the Ukrainians say. In winter, Russia had time to expand its defenses in stages over kilometers. Trenches, anti-tank obstacles and mines make it difficult for the Ukrainian troops and delay the offensive.

The use of cluster munitions is extremely effective – because they can work against all Russian defenses. Unlike traditional steel fragmentation grenades, bombs can easily slip into trenches and make life miserable for defenders. Large-scale cluster bombing could potentially clear minefields. And the bombs easily get behind cover, rendering them useless for the time being.

Russia also recognized this advantage early on and has been making intensive use of cluster munitions since the start of the war.

Ukraine has also used cluster munitions, according to a Human Rights Watch report. The latter denies the allegations – but nevertheless demands precisely this ammunition from its Western allies. As Ukraine’s Reconstruction Minister Oleksandr Kubrakov said in February:

What cluster munitions does Biden provide?

Thus, the Joe Biden administration has approved the supply of cluster munitions to Ukraine. The Washington Post writes that these are mainly M864 artillery shells.

The 155mm shells have a range of 29 kilometers and can carry 72 CBUs. Of these, 48 are M42 bombs and 24 are M46 bombs.

The M42 CBUs have a fragmentation effect and as such are deployed against humans and unarmored vehicles. The M46 bombs carry a shaped charge and behave like tanks when hit against armored targets. These are already badly (better) armored anyway, so that cluster munitions pose an extra risk for them.

According to the Pentagon’s latest reports, the (soon to be delivered) CBUs have a dud rate of 2.35 percent. Experts assume that this rate refers to old ammunition with new fuses. It has a self-destruct mechanism built into it so that the bombs don’t stay in the field forever.

Pentagon spokesman Brigadier General Patrick Ryder said the munitions with the lowest dud velocity were chosen “with great care”.

Ukraine has no problem with it

Meanwhile, Ukraine sees no problem with the use of cluster munitions on its own soil. Referring to the high efficiency of the controversial ammunition, Defense Minister Oleksii Reznikov said:

However, the grenades are only used in the fields and not when attacking an occupied city. Minister Kubrakov dismisses the fact that the Ukrainian advance could be hampered by his own dud: “This is our soil. We determine.”

The UN Human Rights Office in Geneva has since protested against the delivery: “Such ammunition kills and maims people long after the end of a conflict,” a spokeswoman said on Friday. “Therefore, the operation must be stopped immediately.” The appeal is a year and four months late.