The New Hampshire Constitution states: “Retrospective laws are highly injurious, oppressive, and unjust. No such laws, therefore, should be made, either for the decision of civil causes, or the punishment of offenses.” N.H. CONST, pt. 1, art. 23. The Geldhofs take the position that RSA 477:48 (Supp. 1977) may be applied to a lease contract made before the statute’s effective date without violating our constitution. We disagree. In this jurisdiction, the question whether the application of a law violates part I, article 23 of our State constitution is resolved according to an often-stated principle, first articulated by this court in 1826. A statute is retrospective if it “takes away or impairs vested rights acquired under existing laws, or creates a new obligation, imposes a new duty, or attaches a new disability, in respect to transactions already past — ’’North American Manufacturing Co. v.