[ArrogantBustard]

On the other hand, in Orthodoxy there is no concept of a "just war".

I think you may be somewhat misunderstanding what we mean by "just" in this context. It is not to say that the "just war" is a positive good, but rather a one in which we may engage without necessarily sinning. It is as opposed to an "unjust war", which is inherently sinful. It is for this reason Pope John Paul II has always preached against warfare: any resort to war, in order to settle some difference between nations, necessarily means that other, less destructive means, have failed. "Just" war is a last resort, not a first option, and is necessarily something that (as you say) is "inevitable ... thrust upon us and .. certainly practice[d] war against greater evils".

[Kolokotronis]

Actually, I didn't misunderstand. I know the Roman concept and frankly rather like it. But Orthodoxy says that all war is sinful, though forgivable certainly. Which of course is not to say that this particular teaching has stopped any wars in Orthodox Lands that I am aware of. Perhaps one of the other "Orthodoxers" among us has better knowledge of this than me.