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

Sounds like he needs proper application of FM 22-102 (See link)
http://www.ncoer.com/wall.htm

In all seriousness, you cant tolerate this otherwise he will infect the rest of your squad. Actions you can take will depend on whether you are Active Duty or Reserve component. I'm sure there are some very good suggestions in this thread, whatever you do, it must be rectified.

The E-5 in me would have whooped his you know what but the First Sergeant in me would have simply made human offer he couldn't refuse. Either do as you're told to do or simply lose your rank, money, free time and if he still doesn't move, there's nothing an MP can't take care of. As a NCO I may not be able to put my hands on you put the MP's can. Just don't let emotions get you to a place where you're the one going to jail. If you know what I mean.

I almost chocked with my morning coffee reading this post and some of the replies. Be nice and ask what happen because the little shit face might commit suicide. Lord come save our MIlitary. If we have that type of SM that they can't obey the simplest of orders what will happed when they are in commbat? Really, the lets ask what's going on does not apply here. This is insubordination. I would have his Supervisors impart discipline and after all was said and done, investigate onto why the little shitface acted like he owned the world. Hell if I see a SGT shitting flowers and giving out hugs for insubordination to a wet behind the ear E2, I would get that platoon leader and platoon SGT and ensure that all in that platoon know how to follow lawful orders. I would not want that type of cancer infecting my over platoons. I would make it my 1SG priority to ensure training on the correct way to follow lawful orders, adding a smiggen of of Army love and plenty of PT rewards were followed all around. Just as a vaccination to the rest of my platoons. I refuse to take pancies to be around Afhaganis and go to the land of the at-any-minute-there-might-be-a-crazy-trying-to-kill-us that would cause the lives of ANY of my Soldier. And that is how I see it. In the mean time I would start the paperwork on his Art 15 and have it in handy just in case he tries the I have been mistreated shit..... I'll get together with Jag to see how to get that E2 out before that cancer spreads on my other Soldiers if he is a think-headed SOB. I must get a fresh cup-O-coffee!

Guy has no business questioning an E5

In the old Army, the Nco would invite the trooper out back and beat some sense into him.

Address troops " well ladies PFC Smart Ass thinks this assignment is below him so all of you maggots will assist him in his assignment, followed by a full gear 5 mile stroll in thru the woods, then we'll all settle down for a nice personnel and barracks inspection. If were finished with that in time you can all eat lunch. Then we'll ask PFC smart ass how he would like to spend his afternoon?

Pushups until "I" get tired

My immediate reaction would be to de-escalate the situation posthaste. Dismiss the E2 from formation and instruct him/her to wait in a secluded office or other location - seclusion offers opportunity for introspection - until I'm ready to deliver verbal and/or written counseling/corrective action.

At this point, I've achieved my initial objective: to manage my anxiety and the counselee's until he/she has internalized the infraction. This is where a leader's knowledge of motivation and human behavior is imperative.

Depending on the MOS/AFSC (grunt or POG (persons other than grunts)) - and I've been both - and the personality of the counselee, my next objective is to correct the smart-mouthing without jeopardizing the counselee's future potential to use real courage, my ultimate counseling objective.

My reaction can be summed up with two sayings: 1) "Don't eat your young", and 2) "Don't throw out the baby with the bathwater." I hope this information is helpful.

This is a challenge for all NCOs. The first question you need to ask yourself is, "how did I lose control? " As a leader you need to set the example, emit confidence and never allow your men to talk back. I usually would make an example of him on the spot. Then afterwards, I will counsel him. He may have a problem that is eating him, but if he has a hint of defiance during this I would either recommend him for an article 15 or smoke him until he vomits (officially). In reality, I always maintained a policy of "woodline", so if he had a problem with me personally, we would fight it out. The truth is that if you are doing your job right, your guy's would look at your team/squad/platoon as a family and you are the head of that family. Your guys should have shut him up if you guys are being lead properly.

Always pull the Soldier aside let them state there case and counsel the E2, about how respect is honored and the job still has to be completed by that Soldier. After the mission is complete and he still has a issue we can take it up with next higher chain in the Soldiers Command