In this paper, I explore the Defective Intervention effects in the past transitive structures in two dialects of Kurdish, where variation is found in how agreement shows up on the verb. In the Northern dialect, in the presence of a Dative subject, the verb displays full agreement with the Nominative object (in person and number), whereas, in the Central dialect, in the same context, the default third person singular agreement obtains. It will be shown that the Defective Intervention as proposed in Chomsky (2000) and assumed in much subsequent work in the Minimalist Program is not adequate to explain the varied pattern of agreement attested in Kurdish past transitive structures. Drawing on the structural differences in the past transitive constructions in the two dialects, I will introduce a modification into the current formulation of Defective Intervention to the effect that in Dative-Nominative structures, agreement with the Nominative DP is blocked by the intervention of a φ-complete head that licenses the Dative DP and not by the intervention of the Dative DP itself. This approach to Defective Intervention predicts that in structures where the Dative DP is licensed by a φ-incomplete head, the Defective Intervention effects will not arise.
