I agree with that entirely, but I would qualify it by adding that warfare/defense/attack are not anti-Christian per se.'world leadership', modern warfare and the modern meaning of defense and attack, are fundamentally anti-Christian. Therefore, it's hard for someone to engage in any of it and still be a Christian, let alone a Christian leader.
On the contrary, in the Christian Middle Ages (and in any traditional society) the warrior class is second only to the priestly class in honor and dignity.
"Might makes right" is mostly seen as a cynical statement today, and with some justification, but that's because in the modern world the use of might is always combined with deception.
In a Christian world, "might makes right" is one of the fundamentals of just warfare, because might comes from God. The conqueror is only expected to be humane and fair with the conquered.