Flamegrilled, I do not think that Christians are called to be pacifists.
We know that nations at times go unjustly to war, and at other times wars are entered for self defense, to protect the governmental authorities or in order to protect the innocent.
"And some soldiers were questioning him, saying, "And what about us, what shall we do?" And he said to them, "Do not take money from anyone by force, or accuse anyone falsely, and be content with your wages," ( Luke 3:14 ).
"Submit yourselves for the Lord's sake to every human institution, whether to a king as the one in authority, 14 or to governors as sent by him for the punishment of evildoers and the praise of those who do right," ( 1 Peter 2:13-14 )
36 He said to them, “But now if you have a purse, take it, and also a bag; and if you don’t have a sword, sell your cloak and buy one. 37 It is written: ‘And he was numbered with the transgressors’ [a] ; and I tell you that this must be fulfilled in me. Yes, what is written about me is reaching its fulfillment.”
38 The disciples said, “See, Lord, here are two swords.”
“That’s enough!” he replied. (Luke 22)
I think that Christians are called to defend the weak and defenseless. If Hitler broke into my house to take my children I would kill him. Why is it different if he or someone like him breaks into the house of my neighbor in another country?
Exodus 22:2 : "If the thief is caught while breaking in, and is struck so that he dies, there will be no blood guiltiness on his account."
The Bible also tells us to protect the innocent, Deut. 19:10 , "So innocent blood will not be shed in the midst of your land which the Lord your God gives you as an inheritance, and blood guiltiness be on you."
( Rom. 13:1-4 )
“Every person is to be in subjection to the governing authorities. For there is no authority except from God, and those which exist are established by God. Therefore whoever resists authority has opposed the ordinance of God; and they who have opposed will receive condemnation upon themselves. For rulers are not a cause of fear for good behavior, but for evil.
Do you want to have no fear of authority? Do what is good and you will have praise from the same; for it [government; the State] is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath on the one who practices evil.”