One standard criterion for there being objectivity in an area of discourse is that there is conceptual space between what someone thinks to be the case and what actually is the case. That is, participants can be mistaken. This article explores one aspect of the objectivity debate as regards law: does it make sense to say that all legal officials or practitioners in a jurisdiction are mistaken (over a significant period of time) about some legal proposition? The possibility of legal error is important to discourse within and about the law. In contrast to the views of some American legal realists, it is important to deny that law is only what the officials declare it to be. However, as this article argues, claims of long-term global error in law are more problematic. The truth of legal propositions seems to be a complex function of official actions and the meaning of the terms used in authoritative legal texts. Because of the conventional nature of law, there are problems with claiming global error regarding propositions of (within) law, the existence of legal norms, and structural priorities among types of legal norms. At times, the law may in fact simply be what officials (collectively) say it is, over the long term. However, the article also notes areas where claims of long-term global error are more sustainable: where the law incorporates a term from another discourse, or where the law purports to interpret an authoritative text.