Attempts to determine the underlying cause of intervention effects, in which a quantificational or focusing element c-commanding a wh-phrase leads to ungrammaticality, have run the gamut from syntactic (Pesetsky 2000), through semantic (Beck 2006), to information-structural accounts (Tomioka 2007). By presenting novel data from Amharic, a Semitic wh-in-situ language, this paper shows that the empirical basis of these accounts is lacking, and that intervention effects are sensitive to hierarchical structure in a manner not previously considered. Unlike any other language documented until now, and contra the descriptive generalization suggested in Beck (2006) whereby intervention effects are universal, Amharic does not exhibit ungrammaticality when a quantificational or focusing element c-commands a wh-phrase. To explain the latter observation, this paper adopts the hypothesis that interveners are focus-sensitive operators, and that the binding of a wh-phrase by such operators, rather than the required Q operator in C, derives the ungrammaticality of intervention effects (Beck 2006). In Amharic, this paper argues, potential interveners are positioned above C, allowing the necessary relation between the Q operator and the wh-phrase to be established, and hence intervention effects are not found in the language.