The Department of Defense put out an unusually rapid (and blunt) assessment of US Army Corporal Jesse Thorsen’s stint at the Ron Paul rally a few days ago.  In an article that covered the general restrictions of military service and political activities, the DoD said

A combat engineer assigned to the 416th Theater Engineer Company potentially violated these rules Jan. 3 when he stepped onto a stage at Ron Paul’s headquarters in Ankeny, Iowa, during the Iowa Caucus to offer a personal endorsement.

However, it also specifically noted Thorsen was not on active duty at the time, contrary to the CNN reports at the time: 

Although he was wearing his uniform, the soldier was not in an active status at the time, Army Maj. Angela Wallace, an Army Reserve spokeswoman, confirmed.

While seemingly academic, that status will likely play into the military’s response to his conduct, though the response is yet to be decided:

His chain of command is aware of the issue and is considering appropriate disciplinary action to take, she said.