The U.S. fails at irregular warfare because the U.S. doesn't grasp the significance nor understand the role lawfare, psychological warfare and media warfare plays in today's great power competition. The DoD is more concerned about academic definitions of "irregular warfare" and clinging to scholarly ideals and not getting our hands dirty than actually engaging in hybrid warfare. Moreover, the U.S. is too preoccupied with Westphalian ideals of war and peace to understand we really are at war.
The U.S. fails at irregular warfare because the U.S. doesn't grasp the significance nor understand the role lawfare, psychological warfare and media warfare plays in today's great power competition. The DoD is more concerned about academic definitions of "irregular warfare" and clinging to scholarly ideals and not getting our hands dirty than actually engaging in hybrid warfare. Moreover, the U.S. is too preoccupied with Westphalian ideals of war and peace to understand we really are at war.
I would argue they understand all those things very well but choose to focus these things almost explicitly on their own population.