著者

坂田 雅夫

出版者

同志社大学

雑誌

同志社法學 (ISSN:03877612)

巻号頁・発行日

vol.58, no.2, pp.931-960, 2006-06

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各国が締結してきた投資保護条約の多くには、「他の締約国の国民との間で負った義務の遵守」を確約する条項(「傘条項」)が含まれている。この条項は、それが対象としている義務や義務違反行為の性質を条文上何ら限定していないことから、国家が条約の他の締約国の国民との間の契約に反する行為は、全て同時に投資保護条約のこの種の条項の違反になると解されてきた。近年、この「傘条項」を根拠に、投資保護条約が定める仲裁手続きを利用されることが急増し、仲裁付託数の抑制を図るために、この種の条項の適用対象を制限しようとする新たな解釈が判例及び学説において模索されてきている。それらの新たな解釈のなかでも有力なものとなりつつあるのが、国家が立法権や行政権を行使して外国私人との間の契約を無効化した場合のように、国家がその権力を濫用し、通常私人たる契約当事者なら取り柄ない行為を、国家が執った場合にのみ「傘条項」の違反が成立するという解釈(主権的権限論)である。本稿は、この主権的権限論の法的根拠について批判的に検討したものである。Most of the investment protection treaties have the clause (so-called "Umbrella Clause") which promises the observance of commitments entered with the investors of any other contracting party of the treaty. It is generally accepted that this clause protects the investor's contractual rights against any interference which might be caused by either a simple breach of contract or administrative or legislative acts. It is said that this clause is of particular importance because that it is not entirely clear under general international law whether such measures constitute breaches of an international obligation. In recent articles and arbitral awards published in these three years, a different interpretation of the Umbrella Clause is proposed. This newly advanced interpretation say that the government would breach the Umbrella Clause when it abuses its governmental powers to escape from its contractual obligations, and that the Umbrella Clause has no rule about normal contract disputes which the state acts as contractor, not as regulators relying its sovereign powers. Thomas W. Wälde, a most influential writer about investment protection treaties, powerfully argued for this new interpretation at recent article published in 2005. This article critically examines the legal grounds of this newly advanced interpretation of Umbrella Clause. Umbrella Clause was introduced to private drafts of the investment protection treaty in the 1950's and spread from 1959 to many contemporary investment protection treaties. Thomas W. Wälde argued that implied "Original Intention" of drafters of this clause in the 1950's was to internationalize the protection of investment (then mainly concession) contracts with governments against abusive governmental abrogation. And so it would not cover the dispute over contractual performance that are the "merely commercial", with the State not relying on its sovereign powers. But the research of intentions of relatively many members of drafters of Umbrella clause shows that this clause could cover also the small and purely contractual disputes. Many articles and textbook mention the Umbrella Clause also covering the "mere" or "simple" breach of contract. It is of particular importance that, from 1950's to nowadays, text of The Umbrella Clause of Investment Protection Treaties provide that "any" obligations should be observed and don't restrict the Clause to limited disputes. If the implied intention of drafters and contracting States is to limit the Umbrella Clause to the disputes of governmental power's abuses, it would be curious that in recent investment treaties States don't limit the Umbrella Clause application by clear provision in spite of many commentaries in articles and textbook contrary to their implied intentions.