Final answer:
The concept is known as the warranty of habitability, which ensures landlords must provide safe and sanitary living conditions within residential leaseholds.
Step-by-step explanation:
The concept confirmed by the Illinois Supreme Court that a landlord must deliver and maintain any residential leasehold free from defects that would make the dwelling unsafe or unsanitary is referred to as the warranty of habitability. This legal doctrine requires landlords to provide tenants with livable conditions throughout the duration of the lease agreement. The warranty of habitability is implied in every residential lease, regardless of whether it is explicitly mentioned in the lease agreement or not.
Failure to comply with this obligation can lead to various legal consequences for the landlord, including the tenant withholding rent, paying for repairs and deducting the cost from rent, or in some cases, terminating the lease.
The importance of the warranty of habitability is underscored by the impact on tenants' lives. It addresses power imbalances and aims to prevent cycles of poverty caused by substandard living conditions, as mentioned by Desmond in his discussions about inflated rents and evictions.