If Somin is correct, his argument provides support for one of the core arguments of “Semantic Originalism,” that the success conditions of constitutional communication can be met if we assume that the communicative content of the constitutional text consists of the conventional semantic meanings of the words and phrases as combined by shared understandings of syntax and grammar. Any additional communicative content must be delivered by the publicly shared context of constitutional utterance. If Somin is right, then that context is relatively information poor.
Somin does not argue that the public was generally ignorant of conventional semantic meaning–and this seems unlikely, since shared semantic understandings of some sort are required for linguistic communication to succeed.
Solum’s point has a lot of merit. The public need not know as much if all that originalist theory requires of it is an understanding of “conventional semantic meanings of the words and phrases” in the Constitution. I made a related point in my article when I noted that political ignorance is less of a problem for the original meaning of parts of the Constitution that are clear and unambiguous (pp. 24-26). I also suggested that the challenge posed by public ignorance may counsel in favor of literal rather than figurative interpretations of constitutional text, since low-knowledge voters are more likely to be aware of the former (pp. 44-45).
However, semantic meaning is not a panacea for the problem of ignorance. In many important cases, the semantic meaning of parts of the Constitution is ambiguous enough to allow more than one plausible meaning (e.g. – with terms such as “liberty,” “property,” and “equal protection of the laws”). Many of our most important constitutional disputes involve broad phrases like these, to which different people can attach widely divergent meanings, all of them linguistically plausible. In such cases, widespread public ignorance makes it difficult or impossible to pin down an original meaning. Many low-knowledge voters may have been unaware of the dispute and/or had no clear view on how to resolve it.