The big bad Trump bomb that Israel wants so much

The intensifying shadow war between Israel and Iran has long centered on Tehran's nuclear ambitions. While Israel has conducted cyber operations, sabotage missions, and now limited airstrikes targeting Iran’s nuclear infrastructure, particularly at facilities like Natanz, its ability to cripple the heart of Iran’s most secure and sensitive installations remains constrained. Chief among these is the Fordo Fuel Enrichment Plant, a fortified facility carved into a mountain near the city of Qom. To neutralize such a hardened target, Israel would require capabilities currently outside its arsenal, namely, America's GBU-57 A/B Massive Ordnance Penetrator (MOP).

Israel wants Trump to lob his big bad bomb

The GBU-57 A/B Massive Ordnance Penetrator represents the cutting-edge American bunker-busting technology. Designed by Boeing and fielded by the US Air Force, the weapon is a 30,000-pound (13,600 kg) precision-guided bomb specifically engineered to penetrate deep into the earth and destroy fortified underground facilities.

Weighing 30,000 pounds, with a length of approximately 20.5 feet (6.2 meters), the MOP is the largest non-nuclear bomb in the US arsenal. It can reportedly penetrate up to 200 feet of reinforced concrete or 130 feet of moderately hard rock before detonation. The weapon uses an inertial navigation system combined with GPS guidance to achieve high levels of accuracy against static targets. Only large strategic bombers, such as the American B-2 Spirit, are capable of deploying the MOP due to its immense weight and specialized integration requirements. The GBU-57 is specifically intended for missions that involve highly fortified, deeply buried targets of which Fordo is the most prominent example globally.

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Fordo, Iran’s mountain fortress
The Fordo Fuel Enrichment Plant exemplifies Iran’s strategic foresight in protecting its nuclear programme from aerial attack. Constructed in secrecy and revealed only in 2009, the facility is embedded deep within the Zagros Mountains, beneath an estimated 260 to 300 feet of rock. Built beneath 80–100 meters of rock, the facility is immune to conventional airstrikes or standard bunker-busting munitions like the US GBU-28 or Israeli-developed munitions. Its location and construction complicate targeting. Even if the above-ground entrance is destroyed, internal damage might be minimal.

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Fordo is one of the few known facilities where Iran has enriched uranium to near-weapons-grade levels (up to 60%), placing it at the center of Western non-proliferation concerns. For Israel, Fordo is an insurmountable challenge using its current conventional strike capabilities. Its air force, despite its advanced F-35I Adir stealth fighters and precision munitions, lacks the payload capacity and specialized munitions to reach Fordo’s deepest points.

American Bunker buster, Fordo and Israel's strategic limits
Israel’s military doctrine emphasizes preemption when existential threats are perceived. While it has previously succeeded in striking Iraq’s Osirak reactor in 1981 and Syria’s Al-Kibar reactor in 2007, both were above-ground and within a tactical range. Fordo, however, changes the calculus. Israeli aircraft can reach Iranian targets with aerial refueling, but cannot carry a weapon as massive as the GBU-57. Moreover, penetrating and destroying a hardened target like Fordo would likely require multiple MOP-class strikes, potentially over multiple waves which is something only a strategic bomber force could sustain. The Israeli Air Force possesses advanced US-made bunker busters such as the GBU-28, but these are inadequate for Fordo’s depth.

A unilateral Israeli attack involving a large sortie over hostile airspace (for instance, Jordan or Iraq) would entail significant diplomatic and military risk, especially without US coordination or support. As such, even if Israel were to attack Fordo, it would almost certainly fail to destroy the facility entirely without the strategic delivery capabilities that only the US possesses. The fact that only the US can currently field the GBU-57 A/B gives Washington considerable leverage in managing the Israeli-Iranian confrontation. While Israel has long lobbied for access to the MOP, the US has declined to transfer it, likely for a combination of technical, strategic and political reasons. The MOP and its delivery systems are highly classified and involve technology that the US has not shared even with close allies.

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Retaining exclusive control over the means to destroy Iran’s most protected sites allows the US to modulate escalation and maintain strategic ambiguity. The mere existence of the MOP serves as a bargaining chip in diplomatic efforts with Iran, especially under scenarios where military action is threatened but not initiated. The Israeli desire to neutralize Fordo stems from deep-seated concerns about Iran’s nuclear latency. However, unless the US chooses to either directly strike Fordo, Israel is left with limited options such as covert action, sabotage or cyber warfare.

The Fordo facility, in effect, symbolizes the shift in strategic deterrence in the Middle East. Iran has created a threshold defense against unilateral conventional strikes, buying time and leverage. The GBU-57 A/B, by contrast, is the technological antidote but one controlled solely by the US, thus establishing the asymmetry between regional actors and superpowers.

Fordo's impenetrability reflects Iran's deep awareness of its adversaries' capabilities, and the GBU-57 A/B Massive Ordnance Penetrator embodies a rare, game-changing instrument of strategic warfare. For Israel, the path to disabling Iran’s nuclear core runs through Washington, not merely for political support, but for access to a single weapon system that can breach the mountain. Until that equation changes, Israel can't achieve complete destruction of Iran's nuclear capabilities.