If a US army 1-6-4 unit that has been fired upon and is shaken as a result, is fired upon again by another enemy unit in the same turn and then takes casualties, according to its step progression it becomes a 1-5-4 unshaken half squad. If it had remained a shaken (full) squad, it would not have been able to attack in this turn, but having been further reduced to a half (now unshaken) squad, can it then attack in the turn?