Last April, the US military detonated the “mother of all bombs”—a GBU-43/B Massive Ordnance Air Blast (MOAB), with 18,000 pounds of explosives—over an ISIS tunnel complex in Afghanistan. This being the first use in combat of the giant MOAB, its use in Afghanistan generated widespread press attention. In many of the media commentaries, the GBU-43/B was described as the largest non-nuclear weapon in the US arsenal—as powerful, in fact, as the smallest nuclear weapons developed by the United States. In turns out, however, that the GBU-43/B is eclipsed by an even larger non-nuclear weapon, the 30,000-pound GBU-57 Massive Ordnance Penetrator (MOP), dubbed by some the “father of all bombs” to distinguish it from the MOAB. Originally designed to destroy underground nuclear facilities in Iran, the GBU-57 is now being readied for use against North Korea.
It is no secret that the Defense Department is preparing for possible preventive attacks on North Korean nuclear and missile facilities, supposedly intended to prevent the Kim Jong-un regime in Pyongyang from developing an intercontinental ballistic missile (ICBM) capable of delivering nuclear warheads to the continental United States. National Security Adviser H.R. McMaster has openly called for strikes of this sort, sometimes described as the “bloody nose” option. But any such scenario faces two major hurdles: First, a US strike could provoke massive retaliation by the North against South Korea and Japan, producing vast numbers of civilian casualties; and second, it could fail to destroy all of the North’s nuclear and missile facilities, most of which are thought to be hidden in deep underground shelters. So far as can be determined, the Pentagon has yet to come up with a viable response to the first of these (though it is continuing to search for one), but, with the GBU-57, it may have come up with a solution to the second.
It is impossible to minimize the risks of a first-strike “preventive” US attack on North Korea. Even if American air and missile attacks succeed in destroying many of North Korea’s long-range missiles, that country would still be capable, in all likelihood, of raining vast numbers of artillery shells and short-range missiles (some possibly armed with chemical weapons) on Seoul, located only a few dozen miles from the North Korean border, and on other heavily populated areas in Japan and South Korea—probably killing tens or hundreds of thousands of people (including many American soldiers and their dependents living there). This prospect has led some senior Pentagon officials—including, reportedly, Defense Secretary Jim Mattis—to caution the White House against ordering a preventive strike. Nevertheless, there are many indications that the Pentagon is putting in place the means to conduct such an attack—and recent enhancements to the GBU-57 bomb are among the most alarming of those.
The “father of all bombs” was originally developed on a crash basis during the Obama administration to provide the Pentagon with a non-nuclear weapon capable of destroying Iran’s underground nuclear installations. One of those facilities, the Fordow nuclear-enrichment plant, was located in a tunnel complex dug deep into the side of a mountain. Although President Obama was avidly seeking a diplomatic solution to Iran’s nuclear ambitions—ultimately succeeding in 2015, with the adoption of the Iran nuclear deal, formally known as the Joint Comprehensive Plan of Action—his military advisers wanted to be able to destroy Fordow from the air in case the negotiations failed. The GBU-57 was their answer.