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

You make the whole team pay for his lack of
respect and it will get worked out quick.

EMI and candid advice on the side.

Throat punch

Make everyone do pushups till ur exasted

In combat everyone is stressed to the max. I do not care what this lower enlisted guy has going on in his personal life. There is no excuse for talking back. You do what you are told when you are told. This saves lives. Behavior like this needs to be curbed immediately. The MILITARY is in the business of war. If you can't hack it you don't belong. The military is getting far away from a combat ready force when their trigger pullers are too sensitive to follow orders. This is not a nice business. Killing people and keeping your troops alive is hard mentally and physically. You need to weed out the ones that are too weak to deal with the rigors of combat. Fix this joker or chapter him.

Shut the fuck up and do your job!!

Before or after I kick their asses ?

His insubordination was not private. His attitude adjustment therapy shouldn't be either.

Reeeaaady...KILL!

I agree with this article. The Corps with its standing mission could be rolled into the Army ranks similarly as the other specialized Commands.
Just as the Commands of Special Forces and Delta Force have been established within the United States Army, so could the Marine Corps.
Joint Service operations aboard Ship would not change. The Army would be the true Master of World. By Air, Land, and Sea.