Reasonable Doubt and Your Criminal Case

Introduction to reasonable doubt

reasonable doubtEven those whose only exposure to the criminal justice system has come from watching courtroom dramas like Law & Order on television have heard the phrase “reasonable doubt” and know this phrase (and the legal concept it conveys) plays a key role in a criminal case. In fact, “reasonable doubt” is the burden of proof that must be met in a criminal case: a defendant charged with a crime in the State of Arizona (or in any other state or with a federal crime, actually) must have his or her guilt proven beyond a reasonable doubt. Otherwise, the presumption that he or she is innocent – guaranteed by both the United States Constitution as well as Arizona’s constitution – prevails and the person will be acquitted of the criminal charges filed against him. One of the simplest criminal defenses that can be presented involves arguing that the prosecution failed to prove his or her guilt beyond a reasonable doubt.

Burdens of Proof in Arizona Cases

reasonable doubt“Reasonable doubt” is the highest – but not the sole – burden of proof used in Arizona’s judicial system. The precise burden of proof that the court will use in any given situation will depend on the legal issue being decided and the legal rights that would be affected by the court’s action. Generally speaking, the greater and more personal the right involved in the particular action, the greater the burden of proof. Common burdens of proof include:

  • Reasonable suspicion: When a police officer wishes to stop and briefly detain you in a public place, or if he or she wishes to stop you while you are driving your car, the officer must possess reasonable suspicion that you have committed, are in the process of committing, or have committed a crime. Traffic offenses such as driving without a current registration tag or speeding always provide officers with reasonable suspicion to stop your car. Otherwise, the officer must be able to point to specific and articulable facts that support his or her belief that you are somehow connected to a criminal act. A “hunch” or “guess” does not rise to the level of reasonable suspicion.
  • Probable cause: An officer who wants to place you under arrest must possess enough facts that would cause a reasonable and prudent person to reasonably and conscientiously entertain a belief that you are guilty of a particular criminal offense. This is known as “probable cause” to arrest. Probable cause must also exist if police which to search your home or other private location. In that context, probable cause exists when officers have facts that would lead a reasonable person to conclude that a crime has likely been committed or is being committed and fruits of that crime (e., evidence) are likely to be located in the place where law enforcement wishes to search.
  • Preponderance of the evidence: “Preponderance of the evidence” simply requires the proponent of a legal proposition to show that his or her propositions is more likely true than not. This burden of proof is used in most every civil lawsuit, including personal injury suits and business law disputes. If you picture a scale, a plaintiff/proponent of a legal proposition has met this particular burden when the scale has tipped in his or her favor, however slight that might be.
  • Clear and convincing evidence: “Clear and convincing evidence” is the burden of proof used in some lawsuits or proceedings that are civil in nature but that affect an important personal right. For example, before being able to terminate a person’s parental rights to a child the particular individual or entity wishing to sever these important rights must show the parent is unfit by clear and convincing evidence. While not as stringent as the “beyond a reasonable doubt” standard, “clear and convincing evidence” is still a difficult standard to meet. The evidence must be of such quality that a reasonable person concludes the proposition attempting to be proven is “highly probable.”
  • Reasonable doubt: Reasonable doubt is used exclusively in criminal trials (e., there are no civil lawsuits that require the plaintiff or proponent of a claim to prove that claim beyond a reasonable doubt). This is the highest burden of proof available, and it makes sense that it should be used when a person’s property, reputation, and even liberty is at stake. Proof “beyond a reasonable doubt” is proof that leaves a person “firmly convinced” that the particular proposition or claim is true. Proof “beyond a reasonable doubt” does not have to overcome any conceivable doubt. In other words, the prosecution in a criminal case does not have to prove the defendant is guilty with 100 percent certainty.

In general, a “burden of proof” refers to the obligation of one party or the other to present sufficient evidence to convince the factfinder of the veracity of a particular proposition to the degree of the specific applicable burden. Whether the burden of proof is met in any particular case will depend on both the quality and quantity of evidence presented. Criminal defendants have been proven guilty beyond a reasonable doubt by the testimony of one witness, and civil lawsuits have been lost by plaintiffs even though dozens of witnesses and items of evidence are introduced.

Picturing Reasonable Doubt

jury decides reasonable doubt

Each juror is entitled to determine for him or her what constitutes a “reasonable doubt.” Lawyers and judges are generally not inclined and are, in many criminal cases, dissuaded from trying to explain what proof “beyond a reasonable doubt” looks like. Although many courts throughout the United States discourage or even prohibit attorneys from attempting to define “beyond a reasonable doubt,” some have nonetheless tried. Proof beyond a reasonable doubt has been compared to:

  • A puzzle that may not be 100 percent complete but that has enough of the pieces in place that you know what the puzzle is supposed to represent:
  • Knowing that you will have to wear shorts and sunscreen for an August day in Phoenix;
  • Seeing a slightly unfurled flag in the corner of a room, noticing that it appears to have seven red stripes and six white stripes and concluding that the flag is in fact the American flag.

Many courts have warned judges and lawyers alike that attempts to define what a “reasonable doubt” is or what proof beyond a reasonable doubt looks like are likely to leave a jury more confused than they might otherwise be. In a criminal proceeding in Arizona, therefore, neither the prosecutor nor the defense are likely to attempt to define or explain this concept, and they will most certainly draw an objection from the opposing party if they do.

Reasonable Doubt Applies to Each Element that Must Be Proven

reasonable doubt

In a criminal case, the jury will receive a set of instructions before they retire to the jury room to deliberate. These instructions give the jury the legal principles necessary to decide the criminal case. Included in these instructions will be instructions that set out the “elements” of each of the crimes with which you have been charged. Each “element” is phrased as a factual proposition. The prosecution’s burden of proof requires the prosecution to prove each and every element of each and every crime with which you have been charged beyond a reasonable doubt. If they fail to do so, you must be acquitted of that particular charge. So, for example, assume that you have been charged with burglary. Even if the prosecution proves every other element of the crime beyond a reasonable doubt, if the prosecution fails to convince a jury beyond a reasonable doubt that the alleged burglary occurred on a specific day within a specific jurisdiction, you must be acquitted of the burglary charge.

It should also be noted that the burden of proof in a criminal case always rests with the prosecution. Attempts to “shift the burden” and require the defendant to prove his or her innocence are improper and can result in the reversal of a conviction on appeal. So, for example, the prosecutor in a murder case cannot argue that the defendant should be found guilty because “he [that is, the defendant] has never provided police or you, the jury, with an adequate explanation for where he or she was on the night of the murder.” 

The Factfinder of a Case Determines Whether the Burden is Met

reasonable doubt factfinder

Determining whether a particular burden of proof is met in a particular case or hearing is a task reserved solely for the factfinder. In many pretrial hearings (such as hearings set to decide motions to suppress, motions in limine, and/or other pretrial motions that may be filed), the judge will be the factfinder. As such, the judge alone will receive and consider the evidence presented at the hearing and decide whether the evidence presented meets the applicable burden of proof. If you elect to have your criminal case tried in a bench trial, the judge will also act as the factfinder at your trial and will determine whether your guilt has been established by proof beyond a reasonable doubt.

If you elect to have your case tried before a jury, all of the jurors must find that the prosecution has proven you guilty beyond a reasonable doubt. This is referred to as a “unanimous verdict.” If even one juror is not convinced of your guilt beyond a reasonable doubt, the jury will eventually be declared to be “hung” or “deadlocked” and a mistrial will likely be declared. Unless there was evidence that prosecutorial misconduct – that is, misbehavior by the prosecutor that prejudices the jury in some way – contributed to the deadlock, a mistrial will allow the prosecution to select a new jury and try you again at a later date.

Because judges and/or juries determine if reasonable doubt has been met after considering the testimony presented and having the ability to watch witnesses while they testify, appellate courts are hesitant to second guess a trial judge’s or jury’s determination.


Reasonable doubt is an important concept in criminal law cases. It refers to the burden of proof placed upon the prosecution by the U.S. Constitution and Arizona’s constitution. “Beyond a reasonable doubt” is the highest burden of proof in the judicial system: because a criminal conviction can require a defendant to pay significant fines, can damage his or her reputation and standing in the community, and can even result in the forfeiture of his or her freedom or life, it should be expected that the facts necessary to support a conviction be proven using this high standard. A prosecutor must produce sufficient evidence at your trial that a jury is left “highly convinced” that each and every element of the crimes with which you have been charged are true. The obligation to prove your guilt beyond a reasonable doubt always rests with the prosecution – it is never shifted to the defendant.