Nat Lang Linguist Theory (2018) 36:403–443 DOI 10.1007/s11049-017-9381-0 Truncation feeds intervention Two clause type effects in Basque Arantzazu Elordieta 1 · Bill Haddican 2,3 Received: 13 July 2015 / Accepted: 1 May 2017 / Published online: 11 October 2017 © Springer Science+Business Media B.V. 2017 Abstract In the generative literature, clause type effects have typically been mod- eled in one of two ways—“truncation” whereby embedded clauses are structurally reduced relative to root clauses, and intervention, by which non-root clauses have additional material that blocks movement available in root contexts. This paper an- alyzes two clause type effects in Basque—the possibility of verb-initial word orders (V1) and variation in the relative order of Aux, Neg and VP in embedded contexts. We show that these two effects covary systematically across clause types. We present a unified approach to these clause type effects that suggests that these two mecha- nisms interact, that is, that truncation feeds intervention. Omission of a Force head responsible for the *V1 effect in relevant clause types forces a set of operators to remerge in a position where they block movement of negation. VP-Neg-Aux orders in these clause types reflect a smuggling repair operation. Keywords Locality · Basque · Intervention · Verb second · Clause type · Truncation 1 Introduction In the generative literature, clause type effects have typically been modeled in one of two ways—“truncation” whereby embedded clauses are structurally reduced relative B B. Haddican bill.haddican@gmail.com A. Elordieta arantzazu.elordieta@ehu.eus 1 Department of Linguistics and Basque Studies, Faculty of Arts, University of the Basque Country, Vitoria-Gasteiz, Spain 2 Department of Linguistics and Communication Disorders, CUNY-Queens College, New York, USA 3 Department of Linguistics, CUNY-Graduate Center, NewYork, USA