違約方解除之法教義學體系定位

違約方解除既為新的制度疆域，亦是跨界氣旋，對眾多制度將有深層觸動。在“前提”上應拋棄無真正獨有內核的合同僵局，在“理念”上應徹底改造及吸收效率違約，在“樞機”方面應緊扣違約方解除與履行不能及減損義務之關係，在“框架”上要厘清違約方解除與守約方法定解除權之本質區別，並以之與其他關聯制度共同營構寬宥差序格局。於是，此前有關效率的片面之見將被捨棄，但又追隨著更實質的效率之氣旋作用方向。與此同時，違約方解除的闖入為履行不能泛化、履行不能與實際履行抗辯間螺旋式上升、傳統減損義務之下債權人遭遇的苛求等等提供了深刻的省思契機。在框架上拒絕因路徑依賴從守約方法定解除權“剝取”行使方式、生效時間等，拒絕以片面錨定後者“舉輕明重”式地提升前者的門檻，但又因對違約方解除應采差序格局的把握模式，故而在某些案型之下卻又“神似”法定解除權，並聯通其他制度。如此多向併發，拓展新的疆域。

The termination by the breaching party constitutes not only a new frontier of legal systems but also a cross-boundary vortex, exerting profound influence on numerous legal regimes. In terms of the“premise”, it is necessary to abandon contract deadlock that lacks a genuinely unique core; in terms of“concepts”, it calls for a thorough reform and absorption of efficient breach theory; regarding the“key mechanism”, the focus should be on the relationship between termination by the breaching party, impossibility of performance, and duty of mitigation; and as for the“framework”, the essential distinction between termination by the breaching party and the statutory termination right of the non-breaching party must be clarified, and a hierarchical tolerance system should be constructed in conjunction with other related institutions. Consequently, the previously narrow views on efficiency shall be abandoned, but the vortex effect of the more substantive efficiency can still be pursued. At the same time, the intrusion of termination by the breaching party provides a profound opportunity for reflection on issues such as the generalization of impossibility of performance, the spiral escalation between impossibility of performance and specific performance defense, and the excessive demands on creditors under the traditional duty of mitigation. Structurally, the termination by the breaching party should refuse to“extract”constitutive elements such as the way of exercising and the time of effect from the statutory termination right of the non-breaching party through path dependence, and reject to unilaterally elevate its threshold in a“argumentum a minore ad maius”manner by using the latter as a benchmark. However, due to the adoption of a hierarchical structure, in certain types of cases, the termination by the breaching party“resembles”the statutory termination right in certain prescriptive aspects, and links to many other regimes. Such multifaceted approach expands a new frontier.