Recently, the Korean supreme court decided that the principle of extinctive prescription should not bar the past period maintenance claim for child custody, either until a parenting agreement be made between the parents of the child or until a court's maintenance order against the non-upbringing parent of the child be issued. The court's argument is as follows: 1. a parent who has taken the whole responsibility of upbringing his or her child can claim the other party to pay for their child's custody for the past period, even if he or she has not made any parenting agreement with the other and the court's maintenance order has not been issued in advance. 2. the upbringing parent cannot set off his or her (even past period) maintenance claim against the other's, until the specifications of the claim (such as the amount) is determined either by a parenting agreement or by a court's maintenance order, as the maintenance claim "has not ripen to a property right" without an agreement or a court's order. The court concluded from those two arguments that the past period maintenance claim without an agreement or a court's order could not make a "perfect, concrete property right", to which the principle of extinctive principle should apply.
Those arguments 1 and 2 are based on two important precedents on maintenance claim, that is an en-banc decision on may 13. 1994 (92Su21) and a decision on July 4. 2006 (2006Mu751). Though each precedent might be supported in itself, and, at first glance, the deductive reasoning from those precedents to the decision seems a logical necessity, we cannot agree on neither the result nor the reasoning of it. First, the Korean supreme court does not recognize a past period maintenance claim for separated (but not divorced) spouse. Of course, the rationale which bar the past period maintenance claim in general (including for spouse) cannot apply to that for child, as it is not a true maintenance claim but, in fact, a recourse claim (argument 1). But the sharp contrast between the zero (0) extinctive prescription period of the past period maintenance claim in general and the infinite (∞) period of that for child, cannot be justified by anything. Second, the availability of set-off defense might be restricted when it is related to the maintenance claim and the amount of the claim is not determined (argument 2). Even then, however, it is not because it does not make a property right, but because a set-off between unliquidated claims is not desirable.
Conclusively, contrary to the decision, we think the principle of extinctive prescription should apply to the past period maintenance claim for child custody.