In a civil court case such as one of Smith, the plaintiff, versus Jones, the defendant, the burden is on the plaintiff to show or prove by the facts presented into evidence he has been injured by the defendant. In other kinds of civil lawsuits, such as those involving contracts between the plaintiff and defendant, the plaintiff still has the burden. The standard of proof that the plaintiff must meet is the preponderance of the evidence. This means that a fact put into evidence in supporting Smith’s contention Jones was negligent is more likely to be true than false. The degree to which the jury must believe a fact is more likely to be true than not true in order to meet this standard of proof need only be by the smallest degree; 51 percent would be sufficient.
Sometimes the rules of evidence in a given case will have a standard of proof known as clear and convincing evidence. In order to show that a fact presented into evidence is true according to this standard, the plaintiff Smith must show there is a high probability that a given fact is true or that a juror according to the evidence presented would come to firmly believe the fact alleged by Smith was true. This is a greater degree of proof than preponderance of the evidence, but it is not as high as the beyond a reasonable doubt standard required in criminal cases.
In a criminal trial, the plaintiff is not a person or corporation, but the state or federal government as represented by the prosecutor. The prosecutor, regardless of his title, has the responsibility of enforcing the criminal laws of his jurisdiction. The elements of the allegations a prosecutor must prove will vary with the offense charged, but in any event, it must be proven the defendant committed the offense he is accused of and that he intentionally did so willingly. Because the consequences of a criminal conviction are more severe than in a civil lawsuit, the highest standard of proof, beyond a reasonable doubt, is required. This burden of proof is always on the prosecution because a criminal defendant can remain silent if he chooses. This standard means the prosecutor must convince the jury to the point where they firmly believe the defendant is guilty as charged.