Sir - In her article last week, Senator Frances Black demands a referendum on Irish unity in accordance with the requirements of the Good Friday Agreement of 1998 - but fails to address its possible consequences. As I understand it, that agreement recognised the complexities of conflicting nationalist and unionist loyalties and rights in Northern Ireland and replaced the unionist majority abuse of the nationalist minority with a power-sharing arrangement - because that majority abuse had led to an unsuccessful 25 years of revolt that cost 3,500 lives. In other words, a simplistic, rigid interpretation of democracy (that a majority can do whatever it wishes, regardless of the minority) was replaced with a more flexible interpretation.