Reference
How a justice system works
How a justice system works: the stages a case may pass through, the exits at every one of them, and the rights, review and oversight that constrain each institution. An educational map, not a universal procedure.
A justice system is not one institution. It is several, each doing a different job, each able to act only where the law says it may, and each answerable to somebody other than itself. This page sets out the stages a case may pass through and what constrains the institutions at every one of them.
The first thing to unlearn
The familiar picture is a line: police, then a prosecutor, then a jury, then prison. Almost every part of it is wrong somewhere, and the rest of this site is the evidence. Juries do not exist in most systems. In several, the prosecutor is legally responsible for the investigation from the outset rather than receiving a finished file. Most sentences are not custodial. Most reported matters never reach a court at all.
So the model below branches. Every stage carries the ways a case can leave it, because leaving is the normal outcome rather than the exception, and every stage carries a note on how systems differ, because they always do.
Why the jobs are kept apart
The separations below are the reason a justice system has as many institutions as it does. Each one exists so that no single body both creates a case and judges it.
- Police are not courts. Enforcement bodies exercise powers conferred by statute; they do not determine guilt, and the powers they hold are bounded precisely because they act before anything has been decided.
- Prosecutors are not judges. The body that decides a case should be brought is not the body that decides whether it is proved. In several systems the prosecution owes duties to the accused that follow from exactly that separation.
- Defence is not prosecution. The two are not mirror images. The prosecution acts in the public interest, which is not the same as acting to convict; the defence protects the accused person’s legal interests, which is not the same as securing an acquittal whatever the facts.
- Courts do not ordinarily investigate. Some systems give a judge an investigative role, and where they do it is a defined office rather than the ordinary work of a trial court. A court that gathered its own case would be reviewing its own work.
- Correctional authorities do not determine guilt. They carry out a decision a court has already made. That is why the same body must not make it.
- Oversight is not operational command. A body that inspects an institution does not run it and does not decide its cases. Confusing the two produces the expectation that an oversight body can overturn an outcome, which is not what it is for.
- Rights constrain every stage. They are not a benefit conferred at the end. Several of them operate hardest at the points furthest from a courtroom, which is where nobody is watching.
The stages, and the ways out of them
Read the arrows as may. Nothing here asserts that a case moves from one stage to the next, only that the sequence is one a system may use.
Stage 1 · Always present
Law and legal authority
Where does any of this come from?
Nothing in a justice system happens without a legal basis that existed beforehand. Before any institution acts, a law defines the conduct, confers the power, and bounds it.
Ways a case leaves here
- Most law never produces a case at all — conduct is regulated, permitted or prohibited without anything further happening
How systems differ: What counts as law, who makes it, and how it is changed differ fundamentally between systems. Constitutions bind legislatures in some countries and not in others.
May be followed by: A reported event or suspected offence
Stage 2 · Not always present
A reported event or suspected offence
How does a justice system find out that something happened?
Usually because somebody tells it. Most of what a justice system deals with enters through a report rather than through discovery, which makes reporting one of the most consequential and least examined parts of the whole arrangement.
Ways a case leaves here
- Nothing is reported, and the system never learns of the event
- What is reported turns out not to describe an offence
- The matter is resolved without any justice institution — privately, by a regulator, or by a civil claim
How systems differ: Which body receives a report, and whether it must act on one, differ. So does whether an event reaches the system through policing at all rather than through a regulator, an inspectorate or a private complaint.
May be followed by: Law enforcement response · Investigation
Explained on this site
Stage 3 · Not always present
Law enforcement response
Who turns up, and what may they actually do?
Police and other enforcement bodies hold powers that are conferred by statute and bounded by it. What they may do at this point is narrower than most accounts suggest, and the boundaries are the substance of the stage.
Ways a case leaves here
- No further action is taken
- The matter is dealt with by a warning, a caution or an administrative penalty where the system provides one
- The matter is referred to a body that is not a criminal justice institution
How systems differ: Whether policing is national, sub-national or both, whether a gendarmerie exists, and which body holds which power vary more here than almost anywhere else in the system.
May be followed by: Investigation · The decision whether to prosecute
Explained on this site
Stage 4 · Not always present
Investigation
Who investigates, and under whose direction?
Establishing what happened, under legal constraints on how it may be established. The familiar picture — police investigate and hand a file to a prosecutor — describes some systems and not others.
Ways a case leaves here
- The investigation closes without a suspect or without sufficient evidence
- No offence is established
- The matter is discontinued for a reason the applicable law provides
How systems differ: In some systems a prosecutor or an investigating judge directs the investigation from the outset; in others the police investigate substantially independently and involve a prosecutor later. This is a difference in legal responsibility, not in professional courtesy.
May be followed by: The decision whether to prosecute
Stage 5 · Not always present
The decision whether to prosecute
Who decides whether a case goes to court, and on what test?
A decision made against a legal standard, by a body that is not the investigator and not the court. There is no universal charging test, and whether the decision is a duty or a discretion differs by system.
Ways a case leaves here
- No charge is brought
- The case is diverted — conditionally discontinued, resolved by an agreed measure, or dealt with outside the criminal courts where the law provides for it
- The matter proceeds as an administrative or civil matter instead
How systems differ: Germany makes prosecution a duty and then creates statutory exceptions requiring a public-interest judgement; other systems apply an evidential test and a separate public-interest test. Who holds the decision — a prosecution service, an investigating magistrate, in some systems the police — also differs.
May be followed by: Prosecution and defence
Stage 6 · Not always present
Prosecution and defence
What happens between the charge and the hearing?
Two functions prepare the case from opposite positions, under duties that are not mirror images of one another. In several systems the prosecution owes duties to the accused that the defence does not owe to anyone.
Ways a case leaves here
- The prosecution is discontinued before any hearing
- The case is resolved by an agreed procedure where the system provides one
How systems differ: Whether the prosecution is obliged to investigate exonerating circumstances, what the defence may see and when, and whether representation is mandatory all vary. So does whether a public defence institution exists at all.
May be followed by: Adjudication
Stage 7 · Not always present
Adjudication
How is it decided?
A body that did not investigate and did not charge decides whether the case is proved. What that body is, how it is composed, and what it does with the material differ so much that "trial" is a word covering unlike things.
Ways a case leaves here
- Proceedings are terminated by the court without a decision on the merits
- The matter is remitted to another body
How systems differ: Professional judges, lay judges, mixed panels and juries all appear among functioning systems. Whether the court examines the file, hears evidence afresh, or does both varies with the procedural tradition.
May be followed by: Judgment or other disposition
Explained on this site
Stage 8 · Not always present
Judgment or other disposition
What comes out of the hearing?
An outcome, which is frequently not a conviction. Acquittal, discontinuance and findings that lead nowhere further are outcomes of the system working, not of it failing.
Ways a case leaves here
- Acquittal — the case ends and the person leaves the system
- The finding is one that carries no sanction
- A remedy is ordered against the state rather than a sanction against the person
How systems differ: What may be appealed, by whom, and on what grounds differ. Some systems permit appeal against acquittal and others do not, which changes what "final" means.
May be followed by: Sentencing, where applicable · Adjudication
Stage 9 · Not always present
Sentencing, where applicable
What follows a conviction?
A separate decision from the finding of guilt, made on wider material, and structured by law in most systems. It reaches custody far less often than accounts of criminal justice imply.
Ways a case leaves here
- A financial penalty or other order that requires no supervision
- A custodial term whose execution is suspended, so no custody follows
- An order made under mental-health or other legislation rather than as a sentence
How systems differ: England and Wales lists five purposes a court must have regard to; Canada states one fundamental purpose with six objectives and proportionality as a fundamental principle; Germany names culpability as the basis of measurement and places its reintegration goal in the law of execution instead.
May be followed by: Corrections and supervision
Stage 10 · Not always present
Corrections and supervision
Who carries out a sentence, and what happens during it?
A separate function from deciding the case, with its own decisions and in some systems its own courts. Most of the decisions affecting a sentenced person are taken here rather than at the hearing.
Ways a case leaves here
- A non-custodial sentence is completed
- A financial penalty is paid and the matter ends
How systems differ: Who administers custody differs — nationally in Japan, by sentence length in Canada, by federal unit in Brazil and Germany — and whether an execution court exists at all differs with it.
May be followed by: Release and reintegration · Adjudication
Explained on this site
Stage 11 · Not always present
Release and reintegration
How does it end?
Almost every custodial sentence ends, and where release is early it is a judicial decision on stated criteria rather than an administrative one. Two legislatures state in their own text what the period was supposed to achieve.
Ways a case leaves here
- The sentence is served to its end and the person leaves the system
- Supervision is completed and no further obligation remains
How systems differ: German law suspends the remainder of a fixed-term sentence at stated fractions, subject to a public-security condition and to the convicted person’s consent. Whether release is decided by a court, a board or the administration differs by system.
May be followed by: Adjudication
Explained on this site
What applies across all of it
These are not stages. They constrain the institutions at whichever stage those institutions are acting, which is why modelling them as steps would teach the wrong thing.
Legality
Every act of public power needs a legal basis that existed before the act. This is the condition the rest of the system is built on rather than a stage within it.
Applies at every stage.
Explained on this site
Rights
Rights constrain what each institution may do at the point it acts. They are not a benefit conferred at the end of the process, and several of them operate hardest at the stages furthest from a courtroom.
Applies at every stage.
Explained on this site
Access and representation
Whether a person can use the institutions at all: the language proceedings run in, what they cost, whether the person can take part, and how representation is provided and paid for.
Applies at: The decision whether to prosecute · Prosecution and defence · Adjudication · Judgment or other disposition · Sentencing, where applicable.
Evidence and forensic science
What may be used to establish what happened, and the controls that govern it. The constraints run from the moment material is collected, not from the moment it is offered to a court.
Applies at: Law enforcement response · Investigation · Prosecution and defence · Adjudication.
Explained on this site
Review and appeal
The mechanisms by which a legal system says its own decisions were wrong. They create the cycles in this model, and their existence is what makes deference to a decision reasonable rather than blind.
Applies at: Judgment or other disposition · Sentencing, where applicable · Corrections and supervision · Release and reintegration.
Oversight and accountability
Bodies that examine how institutions used their powers, separately from whether any individual case was decided correctly. Oversight is not operational command and does not decide cases.
Applies at every stage.
Remedies
What a person can actually obtain when an institution gets something wrong. A right whose breach produces nothing is a description of how things ought to be.
Applies at: Law enforcement response · Investigation · Adjudication · Judgment or other disposition · Corrections and supervision.
Explained on this site
What the whole thing is for
A justice system is frequently described as an apparatus for punishment. That describes one stage of one branch, and the rest of this site is the reason it is too narrow. Taken together, the arrangements above are how a society maintains lawful public order, establishes what happened when something is alleged, decides whether an allegation justifies bringing a case, lets that case be answered, resolves the question through a body that did not create it, corrects its own errors, enforces the outcome, and returns the person to ordinary life.
None of that is a claim that any particular system does these things well. It is a description of what the institutions are for, which is the thing you need before you can judge whether they are doing it.
Where to go next: why there is no single path through a justice system, how the institutions hand work to one another, or the country pages for how specific systems are actually arranged.