“Big data blacklisting” is the process of categorizing individuals as administratively “guilty until proven innocent” by virtue of suspicious digital data and database screening results. Database screening and digital watchlisting systems are increasingly used to determine who can work, vote, fly, etc. In a big data world, through the deployment of these big data tools, both substantive and procedural due process protections may be threatened in new and nearly invisible ways. Substantive due process rights safeguard fundamental liberty interests. Procedural due process rights prevent arbitrary deprivations by the government of constitutionally protected interests. This Article frames the increasing digital mediation of rights and privileges through government-led big data programs as a constitutional harm under substantive due process, and identifies the obstruction of core liberties with big data tools as rapidly evolving and systemic.