The Charter of Rights and Freedoms  was introduced in 1982. Since then, Canada has experienced more than twenty-five years of constitutional politics and countless debates about whether the Canadian federation is integrating or disintegrating. There has, however, been no systematic attempt to identify general theories about Canada’s constitutional evolution. Patrick James corrects this oversight by using systemism, a concept drawn from the philosophy of science, to identify and assess five theories that fall into the liberal or communitarian paradigms. These theories are examined in the context of major issues such as the role of the courts or the status of Aboriginal peoples, and debates among advocates and critics of each theory are used to work toward a greater understanding of constitutional wrangling in Canada. By adding clarity to familiar debates, this succinct assessment of major writings on constitutional politics sharpens our vision of the past – and the future – of the Canadian federation.