On another thread I brought up the matter of the Bible guaranteeing than a nation that has faith in God has no need of a standing army as he would defend that nation and wins its wars. Why don't you and others like you believe what that part of the Bible teaches you?
I'm sure that many of us Christians do believe in God's promises and would love to see our nation end its warmongering. However, there are many people in our nation that do not have our faith, and those numbers are likely to continue to grow. We can pray, spread the gospel, and wait to see what happens. Also, if you know someone personally who is thinking about joining the military then you can share with them the verses about God's protection, warmongers, and thou shalt not kill. Then maybe that individual will make the right choice to love his neighbors.