With evidence invalidating
James Bradley Thayer reported in 1898 that even English lawyers were surprised by the complexity of American evidence law, such as its reliance on exceptions to preserve evidentiary objections for appeal.
Some legal experts, notably Stanford legal historian Lawrence Friedman, have argued that the complexity of American evidence law arises from two factors: (1) the right of American defendants to have findings of fact made by a jury in practically all criminal cases as well as many civil cases; and (2) the widespread consensus that tight limitations on the admissibility of evidence are necessary to prevent a jury of untrained laypersons from being swayed by irrelevant distractions.
These include the military tribunals in the United States and tribunals used in Australia to try health professionals.
In every jurisdiction based on the English common law tradition, evidence must conform to a number of rules and restrictions to be admissible.
In these circumstances, it would be open to the trial judge to exclude the evidence of the confession under Section 78(1) of the Police and Criminal Evidence Act 1984 (PACE), or under Section 73 PACE, or under common law, although in practice the confession would be excluded under section 76 PACE.The rules of evidence were developed over several centuries and are based upon the rules from Anglo-American common law brought to the New World by early settlers.The purpose is to be fair to both parties, disallowing the raising of allegations without a basis in provable fact.According to Rule 401 of the Federal Rules of Evidence (FRE), evidence is relevant if it has the "tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence." Federal Rule 403 allows relevant evidence to be excluded "if its probative value is substantially outweighed by the danger of unfair prejudice", if it leads to confusion of the issues, if it is misleading or if it is a waste of time.California Evidence Code section 352 also allows for exclusion to avoid "substantial danger of undue prejudice." For example, evidence that the victim of a car accident was apparently a "liar, cheater, womanizer, and a man of low morals" was unduly prejudicial and irrelevant to whether he had a valid product liability claim against the manufacturer of the tires on his van (which had rolled over resulting in severe brain damage).