Promissory estoppel
Promissory estoppel is an equitable doctrine to require payment in the absence of a contract, if:
- defendant promised something to the plaintiff, upon which plaintiff could reasonably rely;
- plaintiff did in fact rely on the promise; and
- plaintiff was harmed as a result, i.e., plaintiff relied to his detriment.
Relief is limited to the degree of the plaintiff's detrimental reliance, most often constituting restoration ex ante the reliance. Plaintiffs cannot expect "the benefit of the bargain," or "specific performance," except in extremely rare circumstances where such is the only way to restore the plaintiff to her ex ante position.
This was codified at Section 90 of the Restatement (Second) of Contracts. Traditional defenders of contract law opposed this approach because it gives a court discretion to award relief even if there is no contract.
The true "departure" from traditional contract law is constrained by the fact that the "justifiability" of the plaintiff's reliance on the defendant's promise is closely scrutinized.
Nevertheless, promissory estoppel exemplifies a movement against the strict view of contract. Professor Grant Gilmore applauded judicial erosion of contract principles in his famous work, The Death of Contract.