US strike on Iran delayed by bunker buster uncertainty: The Guardian

By Al Mayadeen English
Source: The Guardian
20 Jun 2025 00:22
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Trump delays Iran strike amid internal disputes over whether the GBU-57 bunker buster can penetrate Fordow’s deeply fortified nuclear facility.

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In this photo released by the US Air Force on May 2, 2023, airmen look at a GBU-57, or the Massive Ordnance Penetrator bomb, at Whiteman Air Base in Missouri. (US Air Force via AP, File)

In a political bombshell, US President Donald Trump, despite escalating threats to strike Iran, has privately voiced doubts about the very weapon meant to do it. According to The Guardian, a rift has emerged inside the White House and Pentagon over the effectiveness of the GBU-57 bunker buster bomb, casting uncertainty over plans to target Iran’s fortified Fordow nuclear facility. Trump has withheld authorization, questioning whether the 30,000-pound ordnance can penetrate the deeply buried site.

Insiders report that Trump has made it clear any strike would only be accepted if the United States could be absolutely certain that the bomb would obliterate the Fordow enrichment site in its entirety, as per the report.

“It would not be a one and done,” said retired Maj. Gen. Randy Manner, former deputy director of the Defense Threat Reduction Agency (DTRA).

“Fordow could be quickly rebuilt. It might set the program back six months to a year. It sounds good for TV but it’s not real,” Manner told The Guardian.

Despite assurances from defense officials that the GBU-57 might collapse tunnels or disable parts of the site, Trump remains unconvinced and has withheld approval, for now. The Guardian reported, citing sources familiar with the discussions, that he is also weighing whether the mere threat of US direct attacks could bring Tehran back to the negotiating table.

Fordow too deep for conventional bombs?

The Fordow facility, buried deep inside a mountain and reportedly fortified up to 300 feet underground, presents a daunting challenge, as per the piece. While the 30,000-pound GBU-57 is reportedly designed to penetrate hardened underground targets, the Pentagon has long debated its true capabilities against a site like Fordow.

Defense officials familiar with DTRA assessments acknowledge that even multiple bunker busters might only bury segments of the facility or disrupt operations temporarily, falling short of complete destruction.

“It would not be a one and done,” Manner repeated, adding that the weapon might slow Iran’s progress but would not prevent eventual reconstruction.

The DTRA, which has tested the GBU-57 and evaluated its performance, reportedly concluded that permanently disabling Fordow without the use of nuclear weapons would be "extremely difficult".

Plan B is apprehensive

Though some defense experts believe only a tactical nuclear strike could fully neutralize Fordow, White House officials alleged that Trump is not considering such an option. Defense Secretary Pete Hegseth and Joint Chiefs Chairman Gen. Dan Caine have not presented any nuclear scenarios during briefings.

Even with conventional force, the odds are uncertain, the report said. Defense analysts note that achieving the required precision would demand full US air superiority, suppression of GPS jamming, and exact intelligence on Fordow’s internal layout. The bomb has never been tested in a real-world mission targeting such a deeply buried and reinforced facility.

"Israel", which has publicly threatened to act unilaterally against Iran’s nuclear program, lacks both the delivery systems and the ordnance needed to strike Fordow. While Israeli war planners have reportedly floated more unconventional options, including a commando infiltration and internal sabotage plan, Trump has already dismissed that proposal, according to The Guardian, citing sources.

The Guardian claims that Trump’s caution reflects growing awareness of the strategic risks. One official familiar with Pentagon briefings emphasized that Fordow’s deep fortification presents “significant challenges", especially given that the GBU-57 has never faced a real-world target of this magnitude.

As one senior defense official explained, “even with a B-2 stealth bomber, success is far from guaranteed.”

Despite growing pressure from within "Israel" and some US hawks, neither the Pentagon nor the White House has made any official comment. But behind closed doors, the debate underscores the limits of conventional military power and the high stakes of miscalculating the consequences of escalation.