The long-term effect of this has been to open Western societies to immigration, and to impart an ideal of citizenship that, it is hoped, will enable people of disparate origins and backgrounds to live together, recognizing that the real source of their obligations lies not in that which divides them - race and religion in particular - but in that which unites them - territory, good government, the day-to-day routines of neighbourliness, the institutions of civil society, and the workings of the law. Sometimes