Contracts II
Restatement Second of Contracts § 263
Destruction, Deterioration or Failure to Come Into Existence of Thing Necessary for Performance
If the existence of a specific thing is necessary for the performance of a duty, its failure to come into existence, destruction, or such deterioration as makes performance impracticable is an event the non-occurrence of which was a basic assumption on which the contract was made.
Copyright, The American Law Institute