What did the court decide in Marini v. Ireland?
Answered for: New Jersey
In a modern setting, the landlord should, in residential letting, be held to an implied covenant against latent defects, which is another manner of saying, habitability and livability fitness.
New Jersey's Supreme Court recognized an implied covenant of habitability and a tenant's ability to repair and deduct the cost from rent. The sentence above is the court in its own words.
This answer is true in New Jersey and nowhere else on this site. Another jurisdiction is another answer, or an honest gap: see what has been read for New Jersey.