The tradition of permitting the fact finder to draw a strong inference against the party who fails to call a presumably friendly witness has deep roots in New York trial practice. Over 100 years ago, the Court of Appeals held that

In case a litigant fails to produce a person known to be friendly to him and to his cause, who is so situated that he must have knowledge of the facts in issue, the jury is permitted to presume that the testimony of that person would not have been favorable to the party.1

As if further confirmation of this principle were needed, in 2003, the Court of Appeals held in People v. Savinon2 that

When a party truthfully presents a version of events, a fact finder would expect that party’s friend or ally (if knowledgeable) to confirm it.