Expert evidence is increasingly used to establish social and legislative facts during constitutional review. Not only is the use of expertise expanding, lengthening proceedings, complicating constitutional review and limiting access to such review, but many litigants are succumbing to the temptation to plead the law, principles or values using an expert with impressive academic knowledge. In order to reserve value judgments and pleadings for litigants and for evidence to play its role in establishing the social and legislative facts required for constitutional adjudication, courts attempt to circumscribe the role of expertise. This article proposes four boundaries on expertise in order to make constitutional review more accessible. Expertise would be admissible to establish the concrete effect of disputed provisions or little-known historical facts when they are relevant for interpreting or applying the law, but it would not be accepted to establish points of comparative law or to normatively influence the interpretation or application of the law.