A theory recently advanced by Jeffrey C. King in his 2007 book The Nature and Structure of Content identifies the structure of a structured proposition with the logical form (LF) of a sentence expressing it. I will argue that a theory such as King’s cannot work. Any theory that entails that no two sentences that have different LFs can express the same proposition is vulnerable both to an objection based on entailment relations between attitude-reports, and to a more general objection based on the notion of shared content.