Identity, Conflict and Public Space

In ethnic and political conflicts around the world, public spaces are used by diverse groups of people, to express their identity and protest about their beliefs:

in Northern Ireland, contests over flags, parades and memorials have been frequent during the peace process;
as South Africa developed a new democracy, the management of demonstrations by the police became a key issue;
in the post-soviet era, Eastern European countries have slowly come to terms with the rights of people to express their political opinions in public spaces;
and post-9/11, western democracies have struggled to define public spaces for their large Muslim communities.

How is freedom of expression managed in highly divided societies, particularly when they have a history of political violence?