First impression (known as primae impressionis in Latin) is a legal case in which there is no binding authority on the matter presented. Such a case can set forth a completely original issue of law for decision by the courts. A first impression case may be a first impression in only a particular jurisdiction. In that situation, courts will look to holdings of other jurisdictions for persuasive authority.
In the latter meaning, the case in question cannot be decided through referring to and/or relying on precedent. Since the legal issue under consideration has never been decided by an appeals court and, therefore, there is no precedent for the court to follow, the court uses analogies from prior rulings by appeals courts, refer to commentaries and articles by legal scholars, and, of course, its own logic. In cases of first impression, the trial judge will often ask both sides' attorneys for legal briefs.[1]
In some situations, a case of first impression may exist in a jurisdiction until a reported appellate court decision is rendered.
In the 2009 confirmation hearings of Sonia Sotomayor for the United States Supreme Court, Senator Jon Kyl, argued that the New Haven, Conn., firefighter case that Sotomayor and her appeals court colleagues dismissed was a "case of first impression," meaning that Sotomayor could not have been following precedent, as she has argued.[2]
In United States v. LaFleur, 971 F.2nd 200[3], the Ninth Circuit was confronted with the issue of whether or not "duress" is a valid defense to murder under 18 U.S.C, 1111(a), such as that mitigates murder to manslaughter.[4] The court declared "This is an issue of first impression, and our review is de novo."[5]