Trump rules out using a nuclear bomb on Iran: Why that matters 

United States President Donald Trump has for the first time explicitly ruled out the use of a nuclear weapon against Iran, but has not denied US media reports that his administration is considering deploying the US’s most lethal non-nuclear munition, nicknamed the “mother of all bombs” in the near future.

In an interview published on Thursday by right-wing American news site Newsmax, Trump suggested he does not plan to use nuclear weapons, but also clarified that the devastating aerial weapon, the GBU-43/B Massive Ordnance Air Blast Bomb (MOAB – ‘mother of all bombs ) “is not nuclear”.

“I wouldn’t use nuclear. We don’t have to. We’re the greatest nuclear power in the world,” he told Newsmax.

The comments marked Trump’s first definitive statement on the nuclear topic following speculation about a possible atomic conflict earlier in the US and Israel’s war on Iran. They also appeared to confirm speculation that another phase of the war is imminent, likely after the US midterm elections on November 3.

Here’s what we know:

What did Trump say?

Trump told Newsmax that the US might indeed launch another strike on Iran’s nuclear sites, particularly on Pickaxe Mountain, where Tehran is believed to be hiding a nuclear facility deep under layers of granite.

He ruled out using a nuclear weapon or a tactical nuclear weapon.

“I wouldn’t use nuclear. We don’t have to. We’re the greatest nuclear power in the world,” he said.

He also clarified that the MOAB, which CNN reported the US government is considering using, “is not nuclear”.

Responding to a question about whether the MOAB is “tactical nuclear” – meaning smaller nuclear munitions – Trump reiterated that it is not.

“Well, the mother of all bombs is not nuclear,” Trump said. “It’s not nuclear at all. This is just an extremely large bomb.”

Trump declined to say whether he had authorised its use in Iran.

Trump also suggested renewed attacks are likely in the near future. The US cannot end the war now because it has to ensure Iran cannot produce a nuclear weapon, he argued, saying he believes that “if they had it, they would use it, in my opinion, instantaneously”.

Trump also reiterated that the war would end “very soon” whether by force or diplomacy and that oil prices would then drop.

When asked if he would put “troops on the ground”, Trump said: “No, I don’t see that, I don’t see it.” Earlier in the war, Trump had made comments regarding sending in troops, a move analysts said would be devastating for US soldiers because of Iran’s mountainous territory.

What is the ‘mother of all bombs’?

The MOAB carries a massive payload of about 8,500kg (18,000 pounds or 8.5 tonnes) of high explosives. It weighs 9,800kg (21,605 pounds or nearly 10 tonnes) – about the same as four cars – and is just over nine metres (about 30 feet) long. Stealth bombers are too small to carry it, so it has to be deployed by larger, Lockheed C-130 Hercules transporters.

It is designed to explode a few metres above the ground, sending out intense fireballs that can blast buildings and other hard-surface structures within a 1km radius, experts have told Al Jazeera. It is so powerful that a mushroom cloud from its blast has been seen 32km (20 miles) away in tests, the US Air Force has said.

“Its large explosive charge can produce devastating blast effects against exposed personnel, equipment and vulnerable structures,” Brussels-based military and weapons analyst Elijah Magnier said. “Its purpose is to generate an exceptionally powerful blast across a surface area.”

However, Magnier said there is doubt about whether using the massive surface explosive would be effective against deeply buried nuclear installations in Iran. He added that the terrain in Iran could be difficult for larger cargo aircraft to access.

Trump has never explicitly mentioned using a nuclear weapon, but he has also never ruled it out.

Speculation regarding whether Washington might use nuclear weapons was rife in the early days of the conflict, largely because of the extreme nature of Trump’s numerous threats against Tehran.

In April, for example, as Iran enforced a blockade on ships in the Strait of Hormuz, Trump posted on his Truth Social site that “…a whole civilisation will die tonight, never to be brought back again”, if Iran did not agree to a peace deal and reopen the strait.

He also threatened to destroy Iran’s infrastructure, saying a bombing campaign “will be Power Plant Day and Bridge Day, all wrapped up in one”, in Iran.

Experts widely interpreted his statements as a threat of nuclear destruction, but one that still failed to force Iran to the table.

Although Trump largely moved away from his sabre-rattling rhetoric in the following weeks, he reiterated at the United Nations General Assembly in New York last month that he could “annihilate” Iran. He also told the assembly that he believed a deal would emerge after the midterms.

What is a ‘tactical’ nuclear weapon?

“Tactical” nuclear weapons (TNW) are smaller nuclear munitions designed for the battlefield as opposed to strategic nuclear munitions designed for mass destruction.

Some perceive TNWs as having a lesser impact than an atomic bomb, but experts warn that their names are misleading and they can nevertheless be devastating. Their explosive yield, between 0.3 and 50 kilotons, can impact areas within a 500-600km radius.

The US dropped a 15-kiloton nuclear bomb on Hiroshima, meaning that weapon would today be considered a TNW. The US, North Korea and Russia have TNWs in their arsenals, although no country has ever used them. TNWs are not subject to any international treaties and are largely unregulated.

What might another US attack on Iran look like?

With Trump failing to rule out dropping the MOAB, analysts speculate that the US might launch another – perhaps final – intensive bombing campaign targeting Iran’s nuclear and defence sites, particularly Pickaxe Mountain.

The US could also continue its naval blockade on Iranian ports, while providing escorts for commercial ships through the Strait of Hormuz.

Iran has vowed to respond to escalatory strikes by targeting oil and digital infrastructure in neighbouring Gulf states.

Senior defence officials have also warned that Iran will invade its neighbours if the US launches a ground operation, although Trump appears to have ruled that out.

Earlier in the war, he hinted at the possibility of sending ground forces to retrieve some 400kg of “yellowcake” – highly enriched uranium that Washington and Israel claim Tehran has hidden underground.

Trump’s phone calls in March to Kurdish militia groups fighting Iran provoked speculation that Washington could coordinate with them for an invasion, although that did not happen.