The Guardian reports:

Donald Trump has suggested to defense officials it would make sense for the US to launch strikes against Iran only if the so-called “bunker buster” bomb was guaranteed to destroy the critical uranium enrichment facility at Fordow, according to people familiar with the deliberations.

Trump was told that dropping the GBU-57s, a 13.6-tonne (30,000lb) bomb would effectively eliminate Fordow but he does not appear to be fully convinced, the people said, and has held off authorizing strikes as he also awaits the possibility that the threat of US involvement would lead Iran to talks.

The effectiveness of GBU-57s has been a topic of deep contention at the Pentagon since the start of Trump’s term, according to two defense officials who were briefed that perhaps only a tactical nuclear weapon could be capable of destroying Fordow because of how deeply it is located. [Continue reading…]

Darya Dolzikova​ and Justin Bronk write:

For the Fordow Fuel Enrichment Plant and new facility at Natanz at an estimated 80-100 meters, possibly with layers of reinforced concrete, even the GBU-57/B would likely require multiple impacts at the same aiming point to have a good chance of penetrating the facility. Strikes with lesser penetrating weapons could still collapse entry and exit tunnels given good intelligence about their exact layout and location (with some information already available in open-source satellite imagery analysis). However, unless a longer-term campaign were mounted with regular follow-up strikes, efforts to dig down to the facilities to re-establish access and supplies would likely begin almost immediately. [Continue reading…]

The Washington Post reports:

Experts warn that even destroying the uranium-enriching centrifuges deep underground at Fordow would not necessarily mean the end of Iran’s nuclear program.

There may be enrichment sites or caches of nuclear fuel that U.N. inspectors are unaware of, said Richard Nephew, a lead U.S. negotiator with Iran under the Obama administration and now a fellow at the Washington Institute for Near East Policy.

“Even if Fordow was evaporated tomorrow, we would still have massive concerns,” Nephew said. [Continue reading…]