This reference explains why.

https://global.adidam.org/books/not-two-5.html

Plus this reference from the same book, gives a very sobering assessment of the state of the world, pointing out that the two world wars were effectively the destruction of global civilization, and that it has been downhill ever since—despite the seeming technological developments which have relieved the burdens of many people.

https://www.beezone.com/AdiDa/reality-humanity.html

Plus this image from a completely different source shows in stark detail the relationship of the church to the Western imperial project.

https://www.dartmouth.edu/~library/Orozco/panel13.html

Sourced from The Pentagon of Power by Lewis Mumford. A book which described the origins and historical development of the Western Mega-Machine and its drive to total power and control.

ALL of the negative patterns and developments that Mumford warned us about in the book, have come true, and on a scale that he could have hardly begun to imagine.

In the essay I’m kinda purposely vague about where Niebuhr ends and I begin—the reason being that I’m still trying his ideas on and seeing where they go. But I think I can stand by the passage you quote.

It doesn’t mean that violent struggle can be an expression of Christian love—I’ve studied this argument in the past (https://press.princeton.edu/titles/7407.html) and can’t bring myself to accept it. I’m not sure if Niebuhr would or not. In this essay I deal with here, he seems to understand war as a necessary and tragic expression of sin. I’m not sure whether love would enter the picture except perhaps where self-sacrifice is concerned.

I also mean to agree with Niebuhr that Christianity doesn’t equal Gandhian political struggle. Yes, there are resources in the Bible to support it, but there are also resources to support genocide. Jesus’s own efforts seem much closer to anti-political pacifism than political resistance. The point is: I think nonviolent resisters have to take fuller responsibility for their commitments. They can’t just say, “This is what Christianity tells us all to do, so we have to do it.” Instead (and I think this is actually more empowering), they should say, “I am a Christian, and I have come to the conclusion that this is the right thing to do, and I find deep resources to guide me in it in my faith.”

The only trouble—and this was Niebuhr’s crucial point—they can’t go around saying that everyone not doing Gandhian resistance isn’t Christian. That latter quotation I give above—the same thing could be said by a soldier. Point is, Christianity is, and should be, something bigger than nonviolent resistance. Just as it is, and should be, bigger than the religious right’s personal morality agenda. Otherwise, either becomes an idol. The Christian understanding of sin and law does not allow us to confuse our methods with our faith as a whole. But we should not allow that fact to prevent us from making our case to Christians and others about why we believe nonviolence is such an important thing to practice, and such a Christian thing. It’s a subtle difference, but an important one. It forces us to take a fuller responsibility onto ourselves for our political activities, and it affects how to talk to and think about other Christians who disagree with these.