Why the US Is Weighing MOAB Deployment in Iran After the Midterms

The US increased threats to resume hostilities with Iran after the midterms, threatening the use of the largest non-nuclear weapon in the US inventory. During an interview with Newsmax on October 15, Trump said he was considering using the “mother of all bombs,” the nickname for the Air Force’s GBU-43/B Massive Ordnance Air Blast (MOAB). The following Tuesday, Iran's envoy to the U.N., Gholamhossein Darzi, sent a letter to United Nations Secretary-General Antonio Guterres asking for the Security Council to meet to discuss Trump’s and Netanyahu’s threats.

Messages, Bombs, and Insurance Rates

On October 8, President Trump declared on his Truth Social platform that “we will not be attacking Iran any time prior to the Midterm Elections.” Meanwhile, the US is maintaining two carrier strike groups and one amphibious ready group in the Arabian Sea. Open-source reporting by IntelSky indicates an uptick in cargo and tanker flights in the first half of October, which is consistent with positioning air forces in the region. While the Pentagon has been predictably silent on current operations, there are multiple media reports that military planners have been preparing a range of options presented to the president. ABC News reported that its sources confirmed that the MOAB was included in those military options.

The GBU-43/B Massive Ordnance Air Blast (MOAB) is the largest conventional bomb in the U.S. inventory. The MOAB is a 21,600-pound guided conventional bomb that is delivered from the back of an airlifter such as a C-130. It is 30 feet long and just over 3 feet in diameter, and packs 18,700 pounds of high explosive.

The weapon is designed to explode above ground to destroy surface targets such as cave mouths and tunnel entrances. The MOAB’s sole combat use was in 2017 in Afghanistan against an ISIS-K tunnel complex. If the president is considering a large conventional weapon for use against hardened targets in Iran, he might direct the use of the GBU-57A/B Massive Ordnance Penetrator (MOP). The MOP is a 30,000-pound bunker buster that has been used in Iran before and employed from the B-2 Spirit. The MOP was used in Iran during Operation Midnight Hammer, and the Air Force dropped 14 of them during that operation.

The president continues to describe the Iran War as won and the Strait as open, although several facts on the ground complicate that messaging. While oil was moving through the Strait of Hormuz at pre-war levels in September, the Strait remains dangerous, and October saw an uptick in violence. On October 15, two large ships were sunk in the Strait: the GFS Pride, a container ship, and Cape Dao, a bulk carrier. The IRGC also reported a mine strike on Oct 20, a claim disputed by CENTCOM. The United Kingdom Maritime Trade Operations (UKMTO) has recorded 24 ships struck by projectiles, mines, or drones, the worst period since the beginning of the war in March.

Notwithstanding the number of transits, the real indicator is the cost of doing so. Insurance premiums for merchant vessels remain at a very high rate. Insurance rates reflect the actual danger to shipping regardless of messaging from government sources. War risk insurance rates are back at their peak, running between 6-10% of the hull value per transit. This equates to roughly $20 million per vessel per transit for very large crude carriers. Insurance analysis firm Howden Re estimated in March that war claims by insured shipping companies would be $2-3 billion against premiums of $1.5-2 billion.

In May, they noted the pressure on maritime insurance had resulted in mass cancellations of insurance contracts, 1,000% increases in premiums, and losses of vessels. They also updated their estimate of losses at $3 billion, a projection that is one of many drivers keeping insurance rates and the cost of fuel at high levels.

Latest Developments

On Monday, Defense Secretary Pete Hegseth made an unannounced visit to Israel, the U.S.'s co-belligerent in the Iran War. Hegseth posted photos of his visit to US troops in Israel on his official Secretary of Defense X account. Axios reported that Hegseth also met with Israel Prime Minister Benjamin Netanyahu at Ovda Air Base in southern Israel. Neither the US nor Israeli government officials commented on the visit. That same day, Netanyahu posted a video of a call he had with Trump after the US president had endorsed Netanyahu’s reelection bid. Trump reportedly told Netanyahu, "You're the man I want by my side, Bibi."

Meanwhile, Iran’s diplomatic corps has been engaged in a flurry of meetings with regional and international players. Iran’s foreign minister trumpeted Iran’s ties with Russia during the Russian foreign minister’s visit to Tehran on October 19. The visit came in the shadow of Trump waiving congressionally directed sanctions on Russia, and striking a deal to buy Russian diesel. In a meeting with Pakistan’s Army Chief Asim Munir the following day, Iran’s President Masoud Pezeshkian repeated the Iranian position that Iran will not return to the negotiating table as long as the U.S. pressure campaign continues. Pakistan has been the central mediator between the U.S. and Iran, and was instrumental in getting agreement on the June Memorandum of Understanding. The two discussed mediation efforts and regional issues during the meeting in Tehran.

So far, there has been no public response from the United Nations regarding Iran’s letter requesting an emergency meeting of the Security Council, but U.N. officials have not been silent on the war itself. During his daily briefing on Monday, UN official Jorge Moreira da Silva appealed to the United States and Iran to make progress on freedom of navigation around the Strait of Hormuz.

The Hallmarks of a Renewed Offensive

The surge of American forces to the region, together with the uptick in attacks on shipping and both sides’ intransigence at the negotiating table, all point to a resumption of hostilities after Election Day in the United States. Since the United States has a veto in the U.N. Security Council, any vote there is likely to be performative.

The IAEA assessed that Iran is retaining 440.9 kg of 60% enriched uranium as of mid-2025, and the U.S. is demanding it be handed over, a demand the Iranians are so far unwilling to meet. Enrichment to 90% is considered weapons-grade, and there is no indication that Iran has undertaken that step. The International Atomic Energy Agency has renewed its offer to take custody of Iran’s enriched uranium.

Meanwhile, military service members and their families can only watch and wait to see whether the president will launch a new round of attacks or seek a diplomatic solution to the very unpopular war.