Army (and the rest of the DOD) are in need of taking a strong stance on not allowing gang members into the service. This could take the form of a zero tolerance for enlistment of individuals with gang tattoos. Also any finding of gang activity in the background check and discipline for anyone making gang signs in military photos. Current soldiers with gang tattoos would have to have them removed or be discharged. The Army managed to get ahold of the skinhead problem in the 90's, they can do the same with the gangs.
Reed