Christianity and the romans
And Christianity was, among other things, an exposure of the violence of the Roman state towards those who did not share its values. That is what the cross is all about. Christianity went bad when it became appropriated by the Roman empire and the cross went from being a symbol of political oppression to a religious form of state triumphalism. Which is why all Christians should be extremely queasy about any cheap talk of us or anyone else being a "Christian nation".