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.
A question upon some phases of which there is a marked conflict of authority is whether a covenant is to be construed as independent or dependent according to its relation to the remaining covenants when the contract is made, or according to its relation to the remaining covenants at the time that the contract is broken. It seems to be generally held that performance of a number of covenants, especially the vital covenants, on one side, leaving one or more minor covenants unperformed, may turn such minor covenants into independent covenants.1 If the covenant is originally independent, the fact that the time has elapsed within which the covenants on the part of the adversary party are to be performed, or the fact that the event has happened on which the covenants of the adversary party are to be performed, has been held to change such covenant from an independent covenant to a dependent covenant;2 but, on the other hand, it has been held that such covenant remains independent, and that the fact that the party who is to perform such covenant may demand performance of an independent covenant on the part of the adversary party does not make the two covenants dependent, one on the other.3 If a covenant is a precedent covenant when the contract is made, but if performance thereof is not required until the party who is bound to perform such covenant may require the performance of certain covenants on the part of the adversary party, it is held in some jurisdictions that such lapse of time converts such covenants into concurrent covenants;4 while in other jurisdictions it is held that such covenants are to be construed as of the time at which the contract was made, and that the fact that each party may demand performance from the other does not convert the precedent covenant into a concurrent covenant.5
2 Campbell v. Jones, 6 T. R. 570.
3 "And • • the plaintiff who is to execute the conveyance, and who is also the person to pay for it, not having made it, or made a tender of it to the defendant, nevertheless calls upon him by this action to pay the consideration money. The very statement of such a claim is enough to refute it. If these be not dependent covenants, it is difficult to conceive what covenants are so. The very substance of the consideration to entitle the plaintiff to receive the money was the making of the conveyance required, and it is admitted that he has not done it; that makes an end of the question. The case of Campbell v. Jones (6 T. R. 570), was very different from the present; for there the instruction to be given was not to be, and could not in the nature of the thing be, performed at the same time with the payment of the money by the defendant, for which a certain time was limited, whereas no time was limited for giving the instruction. But here the parties have stipulated for the conveyance and the payment to be performed at the same time." Glazebrook v. Woodrow, 8 T. R. 366. 1 See Sec. 2074 And 2082 et seq.