As a devout lefty who thinks America and capitalism need a lot more checks and balances, I have to somewhat disagree with you.
When we talk peace, we are talking relative terms. And I suppose I should also add prosperity into the mix.
I think the West has enabled a period of relative peace and prosperity never before seen. And I think it's getting, overall, better every day. Technology and capitalism, for all their evils, have lifted billions out of poverty and saved billions of lives.