I chimed in, but have mainly found this thread to be rather insulting... (US Para)
I also contributed, but got fed up with people continuously assuming that any killing whatsoever = immoral and you are a bad person for doing it, regardless of who you're saving or killing. (planning to join Canadian reserves this January)
It's about consistency and logic. Although I will certainly find the killing a soldier does immoral according to my beliefs in nearly every single case, I recognize that some people don't find the general act of killing wrong.
What you are doing is making exceptions to a moral belief in order to justify external feelings of hate, passion, confusion, ignorance, frustration, anger, etc.
Follow my logic and feel free to point out where I am missing something (or assuming too much):
1. You believe killing another human being is wrong. This is a fact. The fact that you agree with laws prohibiting the killing of other human beings in your own country is evidence to this. Thus, it is reasonable to assume at this point that you also view the life of human beings to have some "higher significance", or to be "invaluable" (sacred, for the religious...). You get the point. Thus, because it would be illogical for this morality to have cultural, geographic, or time/space limitations or borders, you extend this morality by default to all human beings.
2. You refrain from killing people in your own country, family members, friends, people who anger you, random strangers, people who own more than you do, etc. because you believe it is morally wrong to do so, not because it is socially convenient to refrain from killing any of these people.
3. The very instant you even consider signing up for the military, because you believe it is immoral to kill another human being, is in violation of your morality. Nobody has directly harmed you or your loved ones so as to ignite a biological response of self-defense, vengeance, or protection. You are free from such powerful, passionate emotions. You are safe (relative and ambiguous term, but I assume you can see where I am going), you are willingly signing up for a long-term commitment, a profession, where you will be asked to kill other human beings. You will be pressured into killing other human beings. You will be forced to kill other human beings. You will be asked to help kill other human beings. You will be asked to pressure other soldiers into killing other human beings. You will be forced to force others into killing other human beings. This is the nature of the job, and you know this when you sign up. Just as your "enemy" knows this when he signs up. You holding a gun ready to kill whoever you are told to kill are no more moral than the man that does the same thing 2,000 miles away, or 200 ft. away.
You fight for freedom, though when you signed up, nobody was in our homeland threatening to kill you. You fight for justice, though when you signed up, nobody was knocking down your door with an assault rifle demanding you to hold your hands up, cursing at you, willing to torture you. Nope, that is what you signed up to do because you want to believe that is what the man 2,000 miles across the sea wants to do. You haven't witnessed it yet, but you are willing to do it first. Is that moral to you?
Whatever "ideals" you want to use as an excuse for breaking #1 as stated above, you are fooling yourself. You are letting people in positions of power fool you.
You think I don't know how to shoot a gun? You think I've never shot a rifle? A shotgun? An automatic weapon? I've shot plenty of each, I'm accurate with each. You think I don't believe in freedom? You think I get a twisted pleasure when true terrorists crash planes into American buildings, when they kill soldiers with car bombs? I believe in freedom of every single human being on earth to do whatever the hell they want as long as they do not infringe on my right to do the same. That is freedom. Pointing a gun at someone's head and blasting it off because a 40+ year old president with maids, butlers, body guards, $400,000/paycheck, helicopters, a college degree, jets, etc. tells you to do so for the "safety of every American"? Is that freedom to you?
I have plenty sufficient means to kill you. The president of the U.S. Anybody on earth that I want. That is a fact. I am athletic, at least slightly intelligent, and am a passionate person...I could relatively easily pull off any killing I wish.
I despise American politicians and disagree with the entire ing system that keeps them collecting tax dollars election after election without any significantly greater problem-solving abilities than my own. I despise American foreign policy. I love America, don't get me wrong. I have been to 48 states and have emotional attachments to nearly all.
I tell you this because I too have ideals. I recognize that there are people that threaten my ideals, domestically and foreign. I also value being a "good person" that is morally consistent, and where inconsistencies appear to be present, I support myself with logic. Killing you, the president, the head of Al-Qaeda, whoever would be an act of desperation, the act of a person too weak with words to carry on a peaceful protest, too weak to carry on a conversation. Too weak to show love, when everyone else is expressing hate and indifference.
Whatever "ideals" you are using to justify the killing of human beings that you or some politician in Washington have labeled as "enemy", the fact remains that the physical act of killing remains the same. If you can show restraint from killing your fellow citizens (hopefully out of some moral belief, otherwise you're completely missing the point...), then you can certainly show restraint from killing citizens of other countries.