Self-representation is made more difficult by the typical gulf between paper and practice in criminal cases. In books you can find laws that define crimes, fix punishments for their violation and mandate courtroom procedures. Take the time and trouble to read these books, defendants might think, and they'll understand the system. Alas, the practice of criminal law can't be understood by reading books alone. To experienced criminal defense attorneys, the criminal law appears much the same as a droplet of water appears to a biologist under a microscope -- a teeming world with life forms and molecules interacting unpredictably.

For example, "prosecutorial discretion" -- the power of prosecutors to decide whether to file criminal charges, and what charges to file -- determines much of what actually happens in the criminal courts. Which prosecutor has the power to make decisions, and when those decisions are made, can greatly affect the outcome of a case. An act that looks on paper to constitute one specific crime can be recast as a variety of other crimes, some more and others less serious. What in a statute book appears to be a fixed sentence for a particular crime can be negotiated into a variety of alternatives. In other words, the world of criminal law is vast, hidden and shifting, and defendants enter it alone at their peril. At the very least, most self-represented defendants should arrange for a lawyer to be a "legal coach" and consult with their coaches as needed.