This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
In many cases the act which is selected as a condition is one which one of the parties has the power to perform or not at his option.1 If his performance or failure to perform such act, as the case may be, gives to the other party, by the terms of the contract, the right to treat such contract as discharged, if he wishes to, or to treat it as in full force and effect if he elects to waive the breach, such act is a condition, although its performance or non-performance rests with one of the parties to the contract. If, by the terms of the contract, the performance or non-performance of the so-called condition, as the case may be, operates to discharge the party who had the power to perform such act or not to perform it, and if he is not bound to perform any other or further acts by the terms of the contract, it is apparently improper to call such an agreement a contract at all, since performance on the part of the party who has power to perform or to break such condition is thus purely optional.2 Such act may be a condition, although it rests in the power of one of the parties to perform; but the transaction can not be a simple contract, since the element of consideration is absent. If not under seal, it is not a contract at all. A condition, the performance of which is within the power of one of the parties to the contract, is known at civil law as a protestative condition.3
The contract being free from ambiguity, no exposition is allowable contrary to the express words of the instrument." Kihlberg v. United States, 97 U. S. 398, 24 L. ed. 1106.
17 Tacoma & Eastern Lumber Co. v. Field, 100 Wash. 70, 170 Pac. 360.
18 Magee v. Smith, 101 Wis. 511, 78 N. W. 167.
1 Capital Fertilizer Co. v. Ashcraft-Wilkinson Co., - Ala. -, 79 So. 484. See Sec. 2638 et seq.
2 See Sec. 564 et seq., 572 et seq. and 575 et seq.