The use of a GBU-43 Massive Ordnance Gravity Bomb (MOAB) in Nangarhar Province, Afghanistan, today by the United States is being treated as a major news story and a potential escalation. It may prove to be both, but the sheer explosive power of the ordnance, while newsworthy, may not be as dramatic an escalation as some are portraying it.
Before I explain what I mean, let me clarify something: I am no enthusiast for the ongoing war in Afghanistan. After 16 years, the US is the latest power to find itself fighting a seemingly endless war in a land with a long track record of defeating invaders. I'm not defending either the war or the choice of aerial bombing as a weapon, merely commenting on a tactical decision.
While the GBU-43 is indeed the largest non-nuclear explosive in the current US arsenal, that may not equate to greater lethality. (And the Russians have a bigger one.) Other types of weapons, such as thermobaric or fuel-air explosives, can be extremely lethal. And while the 20,000+ pound bomb is he heaviest in the US arsenal. it is partly a successor to the 15,000 BLU-82 "Daisy Cutter" developed to clear jungle for helicopter landing zones, and later in Iraq for mine clearance.
The GBU-43 was originally developed for use in the 2003 Iraq War, but the war was fast-moving and the weapon is not appropriate for urban areas. Though the weapon was deployed during the Obama Administration and its use planned, the Trump Administration is now claiming credit.
Not every target is suitable for such a weapon; some are better suited to ten one-ton bombs than one ten-ton bomb. The total tonnage dropped in most modern wars is what matters, except for the psychological effort.
Afterthought: If this were purely aimed at collapsing the caves, why even announce the weapon used used? It's a tactical decision using a weapon in the known arsenal, so the decision to publicize was for effect.