Jailhouse lawyer is a colloquial term in North American English to refer to an inmate in a jail or other prison who, though usually never having practiced law nor having any formal legal training, informally assists other inmates in legal matters relating to their sentence (e.g. appeal of their sentence, pardons, stays of execution, etc.)
This same case also determined that unless states provide reasonable alternative, they must permit such action by jailhouse lawyers.
The important role that jailhouse lawyers play in the criminal justice system has been recognized by the U.S. Supreme Court, which has held that jailhouse lawyers must be permitted to assist illiterate inmates in filing petitions for post-conviction relief unless the state provides some reasonable alternative.
The most common reason that restrictions are added is that prisoners have started to provide more formal legal advice.
[2] Cases brought by inmates have also called attention to the need for jailhouse lawyers to have access to law libraries.