So you’re young, you’re fun (by your own definition), and you’ve moved to what’s been called, suspiciously, an up-and-coming neighborhood in the District. Your block has been diagnosed as early-stage gentrification, with one or two spruced up apartment buildings dispersed between the dilapidated early 20th century houses, one of which houses you. The stair railing’s broken, the bricks are chipping, and the window bars need to be replaced. By someone else. Not you.

Javins v. First National Realty Company, a 1970 case, establishes the rule that landlords have to pay to keep buildings up to snuff, not tenants. The plaintiffs, residents of Clifton Terrace in D.C., claimed that they did not have to pay their rent because the apartment complex was falling apart — to the tune of 1,500 separate housing code violations. The Court of Appeals for the D.C. Circuit held that a lease, like every other commercial contract, contains an implied promise that the seller has kept the property in good condition. By turning a property transaction into a contract transaction, the court single-handedly undid a millennium of Anglo-American law. Today’s judicial activism, by contrast, only targets decisions from the past 100 years.

Technically, the case’s ruling — called the implied warrant of habitability — only applies to D.C. but courts in many other jurisdictions came to follow the decision, penned by the great progressive Judge James Skelly Wright. Only a decade eariler, as a New Orleans judge, Skelly Wright led the movement to desegregate Tulane University. Though his Nawlins career could hardly be termed the Big Easy, meeting with Southern resistance at every turn, Skelly Wright, once on the D.C. Circuit, not only overturned nine centuries of property law in favor of the urban poor but handily convinced many other courts and state legislatures to do the same.