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

In the modern Army you probably should kiss his ass.

This is clearly a case of insubordination and could be handled with an article 15. However, I would prefer what our Platoon Sergeants did when they encountered a smart mouth and that to have them drop and do 50 push ups. If they refused, then follow up with the insubordination with the commanding officer.
This is necessary because unity is necessary in a unit.
My basic was pure hell as we ran everywhere, did 10 push ups, chin ups and sit ups before every meal and then told the mess hall was not a recreation area and to move out if we casually ate. Any disruption meant a two mile run. Did it work? Yes, it did and I was prepared for the Tet Offensive in Viet Nam. My Platoon Sergeant was still at Fort Leonard Wood when I returned from Viet Nam and I went there and personally thanked him for preparing us for combat.

In the 1968 USAF, this confused young man would be standing in front of the 1st Sgt. He would be advised of Article 134, Relieved of Duty, assigned to a Work Detail pending Article 15 action by his Commander and possible Discharge. The War in Vietnam was building and the Draft still existed for individuals Discharged from the USAF.

I would tell him that he is currently holding the last rank insignia that points up he will hold in his career and further counsel him/her on the error of their ways. A hard put down immediately executed at the moment beats an official paper trail that often holds no corrective action or an opportunity to repair the damage without making it a big thing. The second offense would be the deserved smoke and scunion.

Last time that happen, the young man and I had a talk with the first sgt. After our little talk the young man knew what to do or L.B.J. would be his next address of residence. He busted his ass and made a good E-4 team leader.

I am fairly certain that my initial response would be to smile broadly and say "Oh, this is going to be fun!"

If the others in the squad liked him, it is likely that their assholes would tighten up quite a bit just hearing that phrase. If they didn't like him, they would probably be working hard to stifle a laugh.

There are always simple solutions to the first time such a thing happens. Extra work while all of his peers coach him and cheer him on generally is something troops don't want to repeat.

Oddly, I used to have other sergeants drop by and ask me for extra detail
suggestions when it came to such things because apparently I was a devious cold hearted son-of-a-bitch with a certain streak of evil. Perhaps because I was already 25 years old when I enlisted and had seen a lot of the business world where there are some truly cold hearted people.

Once, when the First Sergeant at my last duty station (Ft. Hood) saw me coming with a young troop, he figured out what was coming and decided to play along. It started with "Good morning Top! Guess what Private So-and-So gets to do today?" He said "Something really fun I'll bet! and he acted really excited when I told him what I had in mind for the wayward soldier. So happy for him.

I think though, that sitting around with a few E4s discussing such onerous tasks generally meant that the soldiers under their care would eventually hear about it and I seldom had issues. But then again, I was known as being the best sergeant to work with if you wanted to pass the promotion boards or win Soldier of the Month. I had a knack for getting people ready. Of all the things I miss about my Army days, working with younger troops to help them succeed is probably what I miss most.

So, as others have said, the troublemaker might just end up being your best troop if handled correctly.

If the assignment is a lawful order this breach of discipline cannot be tolerated otherwise the moral, cohesion and basic chain of command will be broken rendering the unit under your command unfit to carry out any mission, tactical or otherwise.
You as an NCO or officer must be able to issue orders that you k ow will be carried out in other words Military discipline and structure is not open to debate and or discussion by the soldiers.

That fucker just got double duty and work assignments....got anything else to say?

That fucker just got double duty and work assignments...Period. Got anything else to say?

Private meeting with the individual and the First Sergeant. If the subject in question shows any hint of insubordination at this meeting, he would feel the full force of the UCMJ to include an Article 15. Would further inform this individual if he/she ever exhibited this behavior again. I would begin immediate processing for a general discharge.