The definition of genocide in the 1948 Convention prohibits the destruction of national, ethnic, racial and religious groups. During drafting of the Convention, proposals to make this an indicative list rather than an exhaustive one were rejected. The drafters included political groups within the list, only to reject this as their work was nearing completion. The four protected categories are like corner posts on a rectangular field, and it is not always clear to which category a group belongs. Some belong to more than one category. The theory that that the drafters meant to include all ’permanent and stable’ groups has not gained wide support. When national legislation incorporates the crime of genocide there are considerable departures from the limited list in the Convention.