Abstract—How can host States defend economic emergency measures in investment arbitration? Most States adopt a restrictive interpretation of treaty standards, invoke a NPM clauses or argue Necessity. However, one instrument so far has been overlooked, that is a fundamental change of circumstances. Originating in private law under the rubric of the clausula rebus sic stantibus, the legal principle eventually migrated into public international law where it is today codified in art 62 VCLT. Essentially, the rule operates as a balancing exercise for extra-contractual risks. Due to its history, purpose and structural elements, art 62 VCLT is the right instrument to examine economic emergency measures. Still, host States so far seem reluctant, presumably due to uncertainties regarding applicability and scope. This inquiry demonstrates that such reluctance is unwarranted.

中文翻译：

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经济危机与投资仲裁环境的根本变化

摘要—东道国如何在投资仲裁中捍卫经济紧急措施？大多数国家对条约标准采取限制性解释，援引《国家预防机制》条款或对“必要性”进行辩论。但是，迄今为止，一种工具被忽视了，那就是情况的根本变化。起源于克劳斯拉·史密斯·克·斯坦蒂布斯的私法下的私法，该法律原则最终被移植到国际公法中，今天在VCLT第62条中将其编纂为法律。本质上，该规则可以作为平衡合同外风险的手段。由于其历史，目的和结构要素，VCLT第62条是审查经济紧急措施的正确工具。不过，到目前为止，东道国似乎仍然不愿这样做，大概是由于适用性和范围不确定。这项查询表明，这种勉强是没有根据的。