R2d § 225

Elements: (1) performance of a duty subject to a condition cannot become due unless the condition occurs or its non-occurrence is excused; (2) unless it has been excused, the non-occurrence of a condition discharges the duty when the condition can no longer occur; (3) non-occurrence is not a breach by a party unless he is under a duty that the condition occur.

Common misunderstanding: students think a failed condition is a breach. Subsection (3) is explicit: not unless there is a duty that the condition occur. A pure condition's non-occurrence just discharges the other party's duty: no liability flows. The exception is the promissory condition, where failure both discharges the counterparty AND creates liability.