R2d § 235

Section 235 states two complementary propositions. Subsection (1): full performance of a contractual duty discharges that duty. Subsection (2): non-performance of a duty when performance is due is a breach, unless the duty has been discharged by some other means (impracticability, frustration, prior discharge by agreement, etc.).

The doctrinal move is structural: § 235 tells students what the concepts of "discharge" and "breach" mean at the level of individual duties, not of entire contracts. A party can discharge some duties while breaching others. More importantly, § 235(2) signals that breach follows automatically from non-performance — unless some defense explains why performance is not due. This framing makes the Chapter 20 question precise: has the duty been discharged (in which case non-performance is not a breach), or has it merely not been performed (in which case § 235(2) applies)?

Paradigm for § 235(1): A fully paints B's house as agreed. A's duty is discharged; B's duty to pay the agreed price is triggered. Paradigm for § 235(2): A fails to deliver contracted goods on the delivery date without any excuse. A has breached, and B may seek damages. This connects to the Jacob & Youngs v. Kent materials in Chapter 20: the contractor's deviation from specifications is a non-performance, but the question is whether that non-performance discharges B's duty to pay the remaining balance.

Students often conflate breach with the end of the contract. Push back: § 235(2) says the non-performing party is in breach, but that does not automatically discharge the other party's duties or end the contract. The consequences depend on whether the breach is material — covered by R2d §§ 237 and 241. The section itself is neutral on materiality.

Connect to R2d § 237 (material failure as the non-occurrence of a condition), R2d § 241 (circumstances relevant to materiality), and UCC § 2-601 (perfect-tender rule). In Chapter 20, § 235 is the entry point for the substantial-performance doctrine: if A has performed substantially but not fully, § 235(2) technically applies — the question is what consequences follow.