Impossibility in the thing to be done, not just the ability of the promisor to do it.
performance becomes illegal
specific subject matter of the contract is destroyed
party performing personal services dies or becomes incapacitated
Available where contract was formed on a basic assumption that an unforeseeable event would not occur, the event occurs and makes performance impracticable, and the party seeking discharge is not at fault.
Not available for a bad deal. Requires totally unexpected occurrence.
Total impracticability: -
Goods identified at time of contract are destroyed
Performance becomes illegal
Performance has been made impracticable (unexpected contingency occurred making performance impracticable)
Partial Impracticability - Goods actually produced are apportioned among all buyers.
The UCC allows for a defense of commercial impracticability.
Frustration of purpose
Unex[ected events arise that destroy one party's purpose in entering into the contract. Must not be the fault of the frustrated party, and its non-occurrance must have been a basic assumption of the contract.
Occurrence need not be completely unforeseeable, but must have been unexpected and not realistic.
Non-defaulting party may rescind, or parties may recind by mutual agreement by surrendering their rights under the original contract.
Mutual rescision NOT allowed where a third-party beneficiary's rights have already vested.
WRITING that manifests intent to discharge another party from existing duty.