In the aftermath of Israel’s unprecedented air campaign against Iran’s nuclear and military facilities, President Donald Trump has signaled to defense officials that the United States should only consider joining strikes on Iran if the GBU-57 Massive Ordnance Penetrator (MOP) “bunker buster” bomb can be guaranteed to neutralize the deeply buried uranium enrichment facility at Fordow. According to multiple defense sources familiar with White House deliberations, Trump has not been fully convinced of the GBU-57’s ability to eliminate Fordow’s critical infrastructure and has delayed authorizing U.S. involvement while assessing whether the mere threat of American intervention might bring Tehran back to the negotiating table.
Fordow’s Strategic Importance
Constructed during Iran’s clandestine nuclear program in the early 2000s, the Fordow facility lies nearly 300 feet below a mountain near the holy city of Qom. Its purpose is to enrich uranium to weapons-grade levels in centrifuges protected from aerial attack. Following Friday’s Israeli strikes, the International Atomic Energy Agency (IAEA) confirmed the site contained uranium enriched to 83.7 percent—close to the 90 percent threshold for a nuclear weapon. Fordow’s deep underground placement renders standard munitions virtually ineffective, turning its destruction into a high-stakes technical and strategic challenge.
Pentagon Briefings Reveal Doubts over Conventional Ordnance
In classified briefings to the White House situation room, defense department experts from the Defense Threat Reduction Agency (DTRA)—the military’s lead unit for countering weapons of mass destruction—warned that even multiple GBU-57 strikes might fail to penetrate Fordow’s protective geology. The GBU-57, a 13.6-ton conventional bomb featuring a hardened steel casing and GPS guidance, was designed for deep-buried targets. Yet DTRA simulations suggested that its blast would primarily collapse entry tunnels and bury sections of the facility under rubble rather than destroy the centrifuge halls themselves. In the weeks since Trump’s return to office, senior military planners have cautioned that while the MOP could set back Iran’s enrichment timetable by several months to a year, it would fall short of delivering a permanent solution.
Debate over Tactical Nuclear Options
According to two defense officials who requested anonymity, the DTRA briefings extended beyond conventional weaponry to explore the theoretical use of a tactical nuclear warhead. Burial depth estimates for Fordow—combined with hard rock overburden—led some analysts to conclude that only a low-yield nuclear device would guarantee facility collapse. President Trump was reportedly informed that an initial campaign of GBU-57 strikes could be followed by a nuclear strike if Iran did not cease operations. However, neither Defense Secretary Pete Hegseth nor Chairman of the Joint Chiefs of Staff General Dan Caine presented nuclear options as a viable path to the president, who remains publicly committed to avoiding escalation to nuclear use.
Trump’s “Guaranteed Success” Criterion
White House insiders say Trump has repeatedly emphasized “no strike unless it’s certain to work.” According to a senior official present in multiple meetings, the president asked: “If we drop the MOP and it doesn’t destroy Fordow, what then?” That question has become a mantra for U.S. policy in the current crisis. With his administration awaiting signs that Tehran might return to talks—either with the United States or via intermediaries like Oman—Trump has remained reluctant to greenlight kinetic involvement unless the outcome is decisively favorable.
Diplomatic Calculus and Potential Pathways to De-Escalation
Behind closed doors, U.S. diplomats have been exploring whether the mere threat of deploying the GBU-57 could compel Iran to agree to strengthened nuclear constraints. Officials from the State Department and CIA have urged Trump to pair public warnings of U.S. military capability with secret back-channel overtures, hoping that Iran’s leadership might calculate that acquiescing on Fordow would avert a devastating attack. Iranian foreign minister Abbas Araghchi’s statement that “our responses will also stop” if Israeli strikes cease illustrates this dynamic. Trump’s advisers argue that waiting for a diplomatic breakthrough could buy time to refine targeting data and develop a coordinated strike plan with Israel.
Israeli Limitations and Reliance on U.S. Munitions
Despite its successful raids on Iranian military installations and the assassinations of top nuclear scientists, Israel lacks both the munitions and aircraft needed to penetrate Fordow’s deep vaults. The GBU-57 is exclusively deployable by U.S. B-2 Spirit bombers, which can evade sophisticated air defenses and deliver the weapon with precision via GPS guidance. Even if Israel achieved effective air superiority over western Iran, it could not replicate the Pentagon’s ability to drop Massive Ordnance Penetrators. Consequently, Israeli Prime Minister Benjamin Netanyahu has lobbied hard for U.S. participation, framing Fordow’s destruction as essential to prevent Iran from obtaining a bomb that could endanger Israel and U.S. forces in the region.
Technical Hurdles: GPS Jamming and Target Hardening
Pentagon planners acknowledge that achieving a clean strike on Fordow would require neutralizing multiple layers of Iranian air defenses and electronic warfare systems. Iran’s deployment of GPS jammers in the region has forced U.S. strategists to contemplate decoy attacks, cyber-enabled disruption of jamming networks, and pre-emptive SEAD (Suppression of Enemy Air Defenses) operations. The GBU-57 also demands a stable GPS signal to guide its penetration trajectory; if jamming degrades that signal, the bomb could miss its window of penetration or veer off target. Iranian engineers have further hardened Fordow’s vaults with reinforcements designed to absorb shock waves, complicating any assault.
Expert Reactions: Limited Impact, Rebuild Potential
Retired Major General Randy Manner, a former DTRA deputy director, summarized the consensus among weapons testers: “It might set the program back six months to a year. It sounds good for TV, but it’s not real.” Similarly, international non-proliferation experts warn that destroyed centrifuge halls can be reconstructed, and that enrichment equipment is easily sourced or duplicated, particularly if Iran retains a covert supply chain. The IAEA’s recent disclosure that underground tunnels beyond Fordow’s main chamber remain intact underscores the challenge of truly “knocking out” the program by strike alone.
Strategic and Regional Implications
If President Trump opts against U.S. strikes, Israel may feel compelled to continue limited operations against Iran’s nuclear scientists and missile stocks. However, without targeting Fordow itself, the long-term threat of Iranian breakout capability will persist. A U.S. decision to stand back could embolden Iran’s Supreme Leader Ayatollah Khamenei to accelerate centrifuge installation and withdraw further from the Non-Proliferation Treaty’s restrictions. Regional allies such as Saudi Arabia and the United Arab Emirates—already concerned about Tehran’s influence—may interpret American restraint as strategic ambivalence, potentially spurring them to consider their own defensive options, including nuclear hedging.
Conclusion: A High-Stakes Gamble on Limited Military Tools
President Trump’s demand for guaranteed success before authorizing U.S. strikes on Fordow reflects deep uncertainties over the GBU-57’s effectiveness, the risks of escalation, and the hope that diplomatic pressure might yet achieve what bombardment cannot. Defense officials caution that reliance on the Massive Ordnance Penetrator—even in large numbers—will not permanently eliminate Iran’s enrichment ambitions, and that hard targets like Fordow may require either nuclear options or a protracted ground operation that neither Washington nor Jerusalem currently endorses. As tensions remain at a fever pitch, the coming days will test whether the threat of American military might can persuade Tehran to rein in its nuclear activities—or whether, in the absence of decisive action, Iran’s program will emerge stronger from beneath its mountain stronghold.
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