WA, dear Mussa Saheb!
I am very grateful for your kind comments.
You know that I have served as a doctor and brigadier in the army. In the medical field, no religious or emotional difficulties are encountered since our job is to treat the sick and injured human beings whoever they may be.
Any Muslim American citizen enrolled in combat forces must honestly tell about his concerns and sensitivities to his seniors regarding his deployment. He will find Pentagon and the American forces very accommodating to his concerns.
The Quran forbids Muslims to ally with non-Muslims at the national level.
5:51 O You who have chosen to be graced with belief! (Since they deny the Final Revelation that is the Constitution of your state,) do not take the Jews and Christians as your allies. They are allies of one another. He among you who takes them for allies is one of them. God does not guide those who choose to do wrong. [This verse points to taking allies on a national scale, and not to individual friends. See 60:7-9]
Remember that the "Kingdom of God" exists nowhere today. So, it must be one's own sincere and honest decision. There is no room for any kind of deception.