a1 Department of Linguistics, The Ohio State University
In a 1982 paper in the journal Glossa, Pullum outlined a set of arguments for treating English infinitival to as a defective auxiliary verb. Twenty years later, in his entry on infinitival constructions in The Cambridge Grammar of the English Language (CGEL, 2002), Huddleston argues that several distributional facts about auxiliaries fit poorly with this hypothesis. He proposes, on the basis of significant structural parallels, that to is a subordinator (complementizer). I show that Huddleston's arguments constitute a flawed analysis in CGEL's otherwise superb coverage of English descriptive grammar, and that the facts run strongly counter to his claims, often falling out independently from generalizations about auxiliaries that Huddleston overlooks. Several of these points were anticipated in Pullum's paper, but recent research on an idiosyncratic auxiliary-specific pattern of English nonrestrictive relative clause formation provides a powerful new argument in support of the auxiliary claim. In this respect, as in all others, the assignment of to to the class of auxiliaries provides the simplest and broadest account of its syntactic behavior.
(Received September 08 2010)
(Revised September 05 2011)
(Online publication December 06 2011)
 I am greatly indebted to Geoff Pullum for enjoyable discussions, over many years, about (inter alia) the pros and cons of analyzing infinitival to as an auxiliary, and for extremely helpful feedback on an early version of this paper; and to Bob Borsley for helpful conversations about to and the implications for its analysis of the Auxiliary Stranding Relative Clause (ASRC) construction described below. A preliminary version of this paper was presented to the Department of Linguistics Syntax Group at the University of Essex in 2009; I very much appreciate the input I got from the group, and for the kindness of the Essex department generally during my sabbatical there. Finally, I should like to thank the referees for Journal of Linguistics whose comments made clear to me where I needed to sharpen the details of my argument, and where I needed to drastically condense it. All surviving shortcomings are mine alone.