Recently, Laura Donahue, a professor at Georgetown Law and an expert on digital privacy, came to the Originalism Center at the University of San Diego to talk about her recent article, “The Original Fourth Amendment.” The article is a long one, nearly 150 pages long in a law journal, and it covers the development of search and seizure law through English, Colonial and American history. One of the messages that comes across is the familiar one that the Americans were Whigs, who took one strand of English thought that was protective of liberty, and wrote it into the Constitution. (Another area where some have argued this was true was the First Amendment.)
One interesting question is the meaning of the famous language in the Amendment prohibiting “unreasonable searches and seizures.” Many people who reject originalism or embrace a nonconstraining originalism argue that this language is inherently vague or a delegation to the future. In essence, their argument is that unreasonable could mean a variety of things and therefore judges should decide and give it content based on their view of what would be beneficial.
But Donahue disputes this argument. She argues that “unreasonable” means “against the reason of the common law.” In other words, the Fourth Amendment incorporates the principles of the common law and therefore those principles should be followed. Unreasonable does not involve vague language or a delegation to judges. It has a specific meaning that follows the common law in this area.
Donahue presents some significant evidence for her conclusion. It is significant to note, however, that Donahue’s argument only works if one accepts the view that the Constitution is written in the language of the law — that is, that the Constitution uses terms that have legal meanings. If the Constitution is written in ordinary language, then unfamiliar legal terms could not be found in the document.
Donahue’s interpretation employs legal language in two ways. First, in ordinary language, the term “unreasonable” would not normally be understood as referring to the reason of the common law. Donahue cites to Johnson’s dictionary, who does not refer to the reason of the common law. It is only legal works as well as a legal dictionary that make that reference.
Second, an ordinary language reader would not understand the meaning of the term “unreasonable” even if they knew it referred to “against the reason of the common law.” To understand what that term meant, one would have to be familiar with the common law.
I should hasten to add that I do not regard this feature of Donahue’s argument as a defect. As I have noted before, John McGinnis and I have argued that the Constitution is written in the language of the law and therefore its terms must be understood to include legal terms. I believe that Donahue’s argument is a good example of how we can best understand the Constitution by reference to legal language.