How would you react to an E2 who "smart mouths" you in formation?

Unfortunately this is the BS mentality the lower enlisted have nowadays in my personal opinion. Not all, but quite a few. From my time as a lower listed through Company Commander and as a BB Staff Officer I saw all this time and time again and was astounded and had zero tolerance for it. It was not tolerateed when I was a lower enlisted soldier, nor would I allow it to take place under my command. Regarding how to handle it this soldier would immediately be removed from the formation and or gathering and brought to the side and immediately understand the repercussions of their actions if at that time they continued on the same course they had previously gone the matter would be taking further with counseling as well as brought up to higher leadership.

Back in the 'Day', the command of "Front leaning rest position; MOVE" to remind the soldier who was in charge would take care of the issue by allowing the other subordinates to address the problem... Now then, it seems that "Sociologist, "Social justice worriers, civilian educated "Behavioral Scientist" have changed the dynamics of discipline required in the military. The "Not Square Building" in Arlington, Va. needs to stop looking to the 'Civilian' world in these matters.

I had a Pvt in my squad that tried that. I pulled him aside and calmly & quietly explained that his attitude was going to get him in a world of hurt. I told him he was either going to square himself away or he was going to win up in the brig. I also to him to ask the squad about me. I never had another problem with him.

As an officer in the Fire Department at the ranks of Lieutenant and Captain, I had this happen on occasion, mostly with firefighters working overtime on my shift. They would be given an assignment, I would get the "that's not the way my group does it".

My answer would be, "well, this isn't your group... this is MY group, MY station. Either do what you were told or go home. I can page out for another firefighter who would gladly want the overtime. It's your move now"...

I never had anyone go home.. the financial incentive made them make the right decision.

Lets just say He would Only do it ONCE!

The military tary has procedure to handle this kind of issues. But you won't be a nice guy all time. You need to project leadeship as well as comand and control. You fight for democracy but is not democracy on the military. Two things, loyalty and respect and integrity. The 3 general orders. If you can't handle your team, squad or platoon then you are in the wrong position. If this guy is out of your hands you have to escalate this to your section leader and take proper actions for disrespect an NCO. But themilitary has many ways to take care of this actions.

Immediately remove the individual from the formation to a more private setting, make them remain there alone until you regain your composure and calm your thoughts of laying them out. This individual is the rotten apple that will definitely spoil the barrel. An example must be set for the sake of the unit. This is a UCMJ offense and must be addressed accordingly.

Discipline is what makes a military unit function. Without it the unit is just a pack of lazy young people and older people waiting to become eligible for retirement. The utmost respect must be given to the CoC or else a unit cannot function in combat and will deteriorate during peace time.
The situation described in this question requires swift and decisive action on the part of the “senior E5” and the other NCO’s in this unit. The PFC has either forgotten or ignored what was taught to him/her in Basic Training. The PFC must be taken back to a Basic Training style environment and re-taught some respect. It will require a certain level of aggression and cruelty from the NCO’s. This is what Marine NCO’s are expected to do and it usually works. Other branches of the military could learn a valuable lesson from the Marines when it comes to enforcing discipline. The PFC in this scenario does not have to be chartered out or lose a rank. Some good old fashioned smoking and public humiliation could turn him or her around and lead to a realization that the PFC should straighten up and become a useful member of the unit.

I have run into similar situations. It never pays to jump in before looking. The most disiplinary thing that should be done is remove the Soldiers from the formation remind them no matter what the issue is that caused they to back mouth you; they are still a service member and there is still a position of authority. However you do also need to find out what the issue is before you jump into there space. Everyone has issues and you never know what it is. So think before you jump.

Immediate discussion with the offender who will have his heels locked and at attention out where others may see but not hear our conservation (to make an example). would ask the offender if he would prefer not to be in the military and if so take immediate steps to ensure a fast public discharge and make this discharge is as unacceptable to him as his actions were unacceptable to me and his buddies.
I am thinking Article 15 followed by nothing better than a general discharge. Cant't have this cancer spread to other troops!