I previously commented that in McDonald, Justice Scalia–who usually refuses to join any opinion that cites legislative history–freely joins the Plurality which has nearly a dozen citations to legislative history from the 1860s.
While I attempted to provide a rationale for Scalia’s behavior, both in this blog post and in this article, Justice Thomas actually makes an effort to explain why he relies on the legislative record.
Before considering that record here, it is important to clarify its relevance. When interpreting constitutional text, the goal is to discern the most likely public understanding of a particular provision at the time it was adopted. Statements by legislators can assist in this process to the extent they demonstrate the manner in which the public used or understood a particular word or phrase. They can further assist to the extent there is evidence that these statements were disseminated to the public. In other words, this evidence is useful not because it demonstrates what the draftsmen of the text may have been thinking, but only insofar as it illuminates what the public understood the words chosen by the draftsmen to mean.
The distinction between legislative intent viz legislative legislative history and original public meaning is subtle. At least Thomas makes an attempt to separate the two.