A more thorough explanation:

Definition: A critical stage of proceeding is a term used in criminal procedure to describe the stage at which a person accused of a crime will receive the right to counsel. This right is based on the due process clause of the 14th amendment and the 6th amendment. If this right is denied, later proceedings will be prejudiced. A critical stage of proceeding is any stage in which the defendant's presence has a reasonably substantial relation to their ability to defend themselves. Further cases have concluded that a critical stage of proceeding is one in which the defendant's presence increases the fairness of the proceeding. Examples of critical stages of proceeding include trials, police interrogations, and some pre-trial hearings.

Examples:

• Trials: A trial is a critical stage of proceeding because it is the stage at which the defendant's guilt or innocence is determined. The defendant's presence is necessary to ensure that they have a fair trial and can defend themselves against the charges.
• Police interrogations: Police interrogations are a critical stage of proceeding because they can be used as evidence against the defendant in court. The defendant's presence is necessary to ensure that they are not coerced into making false confessions or statements.
• Pre-trial hearings: Some pre-trial hearings, such as those related to bail or plea bargaining, are considered critical stages of proceeding. The defendant's presence is necessary to ensure that they have a fair opportunity to argue their case and make decisions that will affect the outcome of the trial.

These examples illustrate how the defendant's presence is necessary to ensure that they have a fair trial and can defend themselves against the charges. Without the right to counsel and the ability to be present at critical stages of proceeding, the defendant's rights may be violated and the outcome of the trial may be unfair.