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

Discipline, but Quickly, even If it's in front of the rest of my troops. Basically bring him Right back to their basic training days. Then, after the Alpha Charlie, a Huge write-up to go into his file, the reminder of his oath when he Volunteered for service to his country, and the orders he would obey from those of higher rank. If the situation further requires, send that E2 straight to the main office. This pretty much sidesteps my 3 strike rule, but I'd rather make it known to that individual, along with the rest of the formation that Any lack of respect, discipline, and responsibility for one's actions can, and Will result in consequences. No games, no backing off, period.

Smoke him

What to hear the 'Mom' or "DS Mode' response first?
Mom: Everyone, you know what I want-get it done. As for you, follow me and then he gets yelled at in private.

DS Mode. You have your orders of the day, PVT Shitbag and Squad leader, stand fast. All others, Dismissed. Then if you have seen Angry Cop/Angry Drill Sgt on YouTube, then you know he is going to get such a 'smoke session' and verbal lashing that even his great-grandchildren are going to feel it before they are born. But, seriously, I would be writing some serious paper on him, with the squad leader's help. Talking with his command chain and with them create some serious corrective training-the type of training that will not be humiliation, but teach respect.

A lawful order needs to be followed. Start the process immediately to either get that rolling or get them rolling out, often with some extra "fun time" like corrective custody. I had a "request" to run corrective custody to which I said no thanks. Since a request and not an order felt I was within my rights (as limited as they are in the military). To which it was mentioned how would you like to be in corrective custody? So you want to put me in jail for not wanting to run your jail? And why I am a civilian where that logic I can move on from if an employer tries it. You do not have that option in the military. At least not if you do not want a big negative mark on your discharge.

I’m amazed the cuestión is even asked! Who’s in charge!? I like to believe someone handled it.

The monster emerges and life as he knew it is about to change. Everyday he is there

Dismiss everyone else...invite the young lad to step inside the barracks...thump the living shit out of young blood thus realigning his military compass...make sure the lad gets in one punch such that you can claim 1) self defense 2) charge him with conduct unbecoming 3) insubordination to a Staff NCO 4) call his parents letting them know junior will be home this weekend 5) call the MPs and 6) notify the platoon commander or appropriate CO so the facts of the case do not become cloudy over time.

PV2 is about to have a long day. Immediately after formation , PV2 and squad leader will stand fast . I will make an example of him and squad leader, the squad leader for allowing and letting this happen and PV2 for the action

1st of all, all the NCO’s in my unit would be all over him before I could even react, so when you ask me what I would do, sit back and enjoy the show.

I’ve trained my NCO’s on the proper way they as NCO’s should act, disrespectful actions to officers or NCO’s will be handled quickly and aggressively.
We as leaders set the standards for lower enlisted to follow.

AATW

Also, you might let them know that you are not a oc fresh out of college.. I know in the army I had a special forces DS and he told us to basically give no fucks about ocs guys