As Israel's large-scale airstrikes against Iran continue, U.S. President Donald Trump is deliberating whether to deploy the military's massive penetrating bomb, GBU-57 (also known as the bunker buster), against Iranian nuclear facilities. This bomb is considered the only conventional weapon capable of striking Iran's key enrichment facilities, installed in underground rock formations several dozen meters deep.
On the 16th, President Trump returned home a day earlier from the Group of Seven (G7) summit, stating, "If you saw what I saw, you would understand the need to return as quickly as possible." Immediately after returning, he convened a National Security Council (NSC) meeting at the White House to discuss the possibility of U.S. military intervention against Iran. Before the meeting, he expressed a tough stance on social media (SNS), saying, "Everyone must leave Tehran immediately" and mentioned that Iran should have "signed the (nuclear) deal."
U.S. media reported that President Trump is at a crossroads over whether to strike the Fordow nuclear facility at Israel's request or to continue pursuing a diplomatic solution. The New York Times (NYT) analyzed, "If Trump decides to use the bunker buster, it could signify a full-scale U.S. military intervention in the war."
The GBU-57 is a massive penetrating bomb (MOP) weighing 30,000 pounds (approximately 13.6 tons), designed to penetrate over 60 meters underground and strike targets with precision. It can penetrate up to 60 meters of high-strength reinforced concrete and about 40 meters of rock, and can only be carried by the U.S. Air Force's B-2 stealth bomber.
The U.S. military developed this bomb to strike fortified underground facilities in North Korea, Iran, China, and Russia, and it is reported to currently possess about 20 units. A single B-2 can carry two GBU-57s and has the capability to reach anywhere in the world within a few hours.
Israel has already conducted airstrikes on Iran's Natanz nuclear facility, but it has yet to attack the Fordow facility, which is buried much deeper underground. The Fordow facility is located about 140 km south of Tehran in the mountainous region of Qom, underground at a depth of 80 to 90 meters, and is a key strategic facility for Iran capable of producing highly enriched uranium. Originally built covertly without notification to the international community, this facility is where uranium that can be used to manufacture nuclear warheads is enriched, making it a top target of concern for Israel.
However, Israel does not possess bunker busters or B-2 bombers. Therefore, many analysts believe that disabling Fordow without U.S. weapon support is virtually impossible. In this regard, The Wall Street Journal (WSJ) reported, "Single MOPs are insufficient for fortified targets like Fordow, and multiple B-2s must drop bombs consecutively on the same target to increase the chances of destruction."
The International Atomic Energy Agency (IAEA) recently confirmed that some ground testing facilities at Natanz were destroyed in the Israeli airstrikes. Experts point out that if the Fordow facility remains intact, which is buried deeper than Natanz, Iran will maintain its technological foundation for nuclear weapons manufacturing.
Some suggest indirect methods such as cyberattacks or power outages in addition to deploying the bunker buster, but military experts evaluate that "ultimately, only the GBU-57 can completely neutralize that target."
Public opinion in the U.S. on the use of the GBU-57 is divided. President Trump noted, "I want to say to those who say, 'Do nothing to stop Iran's nuclear program,' that 'that's not real peace,'" indicating a leaning towards usage. Hardliners within the Republican Party are also advocating for full support of Israel, but the non-interventionist camp, which opposes involvement in the Middle East, is expressing caution.
If Trump decides to deploy the GBU-57, it is suggested that this could lead to a full-scale U.S. military intervention. On the other hand, there are interpretations that he is still utilizing the bunker buster as a tool of negotiation pressure. Regarding this, the U.S. government has not yet revealed its final policy.