Yeah. Mandatory service, NCO reserve rank.
I don't know what NCO is. but there are some rumors that being a military personnel might cause some problem in getting visa. actually for some countries, say north korea, it's not rumor and they practice this. because they (US) don't want to transfer some critical technologies to other nations by educating people with military background. having said that, I am not sure this really addresses your concern or not. that's what I heard.
Even if the US government has this incentive, the admissions committees at schools do not, and the government has no control over who they admit (besides through offering funding and I doubt there is any difference in the available government funding depending on whether you've listed a military rank on the CV for your admission application or not). On the other hand, it seems like there could be upside to including it, since it can highlight your leadership skills and ability to work in a team, as HappyQuark said.