Due process as a notion of basic fairness has deep roots and broad intuitive appeal. It is a guarantee, stretching back at least to Magna Carta, that government’s most feared impositions on those within its reach — using coercive powers to take away our lives, our liberty, or our property — can only be accomplished through processes that have qualities of regularity and impartiality under rules adopted through mechanisms that historically carried the hallmarks of legitimacy, generality, and neutrality. The same instincts that underlie due process guarantees also inform the structural protections that are the central features of our Constitution. The goal under either label is to protect liberty by regulating the way government goes about setting and applying legal rules. The intuitive appeal of the notion of “due process,” however, at times has obscured the limited reach of the core concept, which is restricted in both what it applies to and what it requires. Transformation of due process from that core to a looser constraint that can be shaped to fit particular notions of good governance has produced serious failures, both encouraging episodes of judicial adventurism that invade space reserved to electoral-representative processes (the story of “substantive due process”) and weakening protections against inappropriate exercises of official discretion. Reliance on softer notions of due process may be especially problematic in respect to questions of administrative process, which often lie outside the ambit of appropriate due process constraints. Even where due process does apply, other legal rules strongly influence the degree to which administrative processes work and frequently provide better avenues for constraining them. Addressing directly the problematic nature of many delegations of authority to administrators and of inappropriate judicial deference to administrative determinations by and large will be preferable to due process challenges to administrative action. Due process can be a complement to reinvigorated delegation constraints and reformed deference rules or a partial substitute — used to compensate for failure to properly reform those doctrines — but it is at best a “second best” option.