Unilateral performance is pretty solid evidence that there really was a contract -- for why else would the party have performed unilaterally? Almost the whole purpose of contracts is to protect the party who performs first from being taken advantage of by the other party, so if a party performs first there is some basis for inferring that he had a contract. The inference of contract from partial performance is especially powerful while the nonenforcement of an oral contract leaves the parties free to pursue their noncontractual remedies, such as a suit for quantum meruit (a form of restitution), Farash v. Sykes Datatronics, Inc., 59 N.Y.2d 500, 503, 452 N.E.2d 1245, 1246, 465 N.Y.S.2d 917 (1983); Robertus v. Candee, 205 Mont. 403, 407, 670 P.2d 540, 542 (1983); 2 Farnsworth on Contracts, § 6.11, at p. 171. The partial-performance exception to the statute of frauds is often explained (and its boundaries fixed accordingly) as necessary to protect the reliance of the performing party, so that if he can be made whole by restitution the oral contract will not be enforced. This is the Illinois rationale, Payne v. Mill Race Inn, supra, 152 Ill. App. 3d ...