The social justice crowd seem to enjoy expressing themselves on their bumpers slightly more than the rest of us. I’m not sure to which stereotype this plays—poor, bohemian hippie who doesn’t have to worry about resale value (because the car had none originally), or rich, progressive snob who doesn’t have to worry about resale value (either because the BMW dealership takes them off when you trade it in, or because it saves the next owner the trouble of applying the stickers themselves). But I do know that it shows an appalling naivety. Let me explain.
Two bumper stickers I have seen read “No justice, no peace (know justice, know peace)” and “If you want peace, work for justice.” Of course, by justice, they mean social justice—personal justice (getting what we deserve) being something that creates more discontent than peace (because we all think we deserve better than we get). That is, if you want domestic harmony, redistribute resources to groups who have less (and want more).
One does not have to be a very good student of international relations to realize the futility of that tactic.

It may seem odd to apply a lesson from international relations to domestic politics—normally we work the other direction—so let me begin somewhat closer to home: the firing range. In 1900, the Deutsche Waffen- und Munitionsfabriken began producing the Parabellum pistol (known popularly after its designer, Georg Luger). They took the name from their motto: si vis pacem para bellum (if you seek peace, prepare for war).
Though I have no idea why particularly the company adopted that motto, it does sound in perfect harmony with German foreign policy at the time. Germany became a unified nation-state rather late in the game (in fact, only about 30 years prior), and found that other nation-states had already created their empires—which gave them access to important resources. Germany sought its “place in the sun,” arguing for what it saw as a more equitable division of (access to) resources, just as a new plant must elbow others aside to escape the shade of taller plants. Germany was just as deserving of colonies as the others (which is literally true, as no state deserves them), and sought to redress the imbalance in recognition of its status as a full “great power.” It was necessary to prepare for war to achieve peace, as peace meant a status quo acceptable to Germany.
Similarly, Adolf Hitler would argue a generation later for Lebensraum, a claim that Germany deserved “room to live.” By this he meant claiming resources by choking out those (particularly Slavic nations) currently subsisting on them. Germany deserved these resources; it was only just that they be redistributed to Germany so that it could become as strong as the other powers, to achieve its destiny.
Please note: I include this claim because of its nature, not the nature of those who made it. I do not thereby insinuate that the social justice crowd are Nazis. They may be totalitarians, but they are progressive rather than populist ones; that is, one may be a socialist totalitarian just as much as a national socialist one.
But note as well the results in both cases. Obtaining some colonies did not satisfy German claims; it continued them. Likewise, “appeasement” is now a pejorative term, so spectacularly did taking resources from one group and giving them to another fail to create peace, in that time or this. More equitable distributions of resources do not create peace; in fact, the redistribution itself seems only to prompt more claims for the use of the mechanism.
Let us turn a more hopeful eye, however, to Germany (and Japan, who made similar claims) after World War II. The liberal postwar system the U.S. helped create allows states to promote their status, as it were, through the system. That is, states can gain or lose, can change the status quo, without having to forcibly deprive others of resources. What is the nature of that system? Free trade. States can outbid others for resources, rather than arm wrestle them. Germany and Japan could become great powers through trade, rather than conquest—and so could China, India, and Brazil. The system allows for a peaceful change of the status quo, and it gives rising states an interest in maintaining the system. Of course, those who suffer from such revision may seek redress, but they too can seek it through the system.
The lesson for domestic politics is clear. Yes, to know peace, we should work for justice. But the justice we should seek in order to ensure peace is procedural, not distributive.