United States of Smash is the most powerful technique in All Might's vast arsenal. It is a smash attack that concentrates all of One For All's remaining power into All Might's fist.
All Might delivers an incredibly powerful punch and smashes his target into the ground. The attack appears to compile the strength of All Might's other smash attacks into one spectacular move.
The impact of this smash is so strong that, upon striking All For One, the wind pressure created from its delivery left a massive crater in the ground and spawned a twister strong enough to carry nearby buildings.
The influx of power received was such, that All Might's broken right arm was instantly restored to full capacity, albeit it only lasted for a single strike.