This assignment starts with a list of popular peace quotes. Also included are a number of quotes created by schools, maybe for some kind of contest. Another teacher I worked with compiled the list, but I took it and created an analysis worksheet that will get students thinking a bit more about the usefulness of such quotes.
The worksheet is 12 short answer questions. One has them creating their own quote, of course. The point, however, is that quotes alone won't fix the world, and the worksheet at least touches on this. You, as the teacher, can expound further. Great for groups. Link to Google Doc so it can be done with your in-class computers or on a lab day.
We used it in the war unit and War and Conflict class, but it certainly works in social studies just as well. Whether your district is full of doves or hawks, this assignment allows the students to consider the alternatives to war without preaching.