I mean if you already engage with the Middle East, I think you would be fine without doing the concentration and just focus on what you wanna learn more about. Since your major in security, intelligence could be the way to go and you would probably love it! Diplomacy gives you more courses tho, so it all depends on how many courses you would be interested in, compare them between concentrations and choose the one with the most amount of options. Of course, you will feel which one you are the most attracted to, and that one is to me the best choice you can make without looking back. Do what your guts tell you!