There is a bumper sticker that has been around for years: "If you want peace, work for justice." I have always hated that bumper sticker. It always rang false to me, and now I know why. Working for justice will almost always bring about a war. And whose justice are we working fo, anyway? Justice as we understand it is different for each person and is completely subjective.
No, if you want peace, you need to work for mercy. It's a much harder fight, but well worth it.