sentences:  While, during the 1970s, the Brigade had been the most active of the IRA's command areas, in the 1980s and 1990s, the IRA's rural units became relatively more important within the organisation.Informers were one aspect of this shift, other factors cited include, "the increasing sophistication of the IRA's enemies in Belfast and Derry," and the electoral strategy of Sinn Féin, which meant that, "In Belfast IRA operations had been scaled down.