This research is designed to help understand the controversial issue, International minimum standard, in the international investment rules(FTA Investment Chapter, BITs) and to guide the direction of discussion on such issues.
More than 2000 BITs were ratified during the second half of the 20th century, Most of the bilateral and regional investment treaties (more than 2000) almost uniformly provide for fair and equitable treatment of foreign investments, and provide for full security and protection of investments. Moreover, most of them include an obligation to provide foreign investors with the "minimum standard of treatment" to which they were entitled under customary international law. Investment treaties generally provide little guidance on the content of the minimum standard of treatment, but instead define it by reference to the customary international law. Therefore the customary international law does play an important role to the extent that it defines the minimum standard of treatment.
The minimum standard of treatment was a broad concept intended to encompass the doctrine of denial of justice along with other aspects of the law of state responsibility for injuries to aliens. Although the minimum standard of treatment has a long pedigree in international law through its roots in the ancient doctrine of denial of justice, its content has always been highly indeterminate, and the discussions of what types of measures it prohibits have largely focused on how egregiously a government's conduct offends the sense(s) of justice of the members of a tribunal in order to violate the standard. Recently the vagueness of the minimum standard of treatment and its fair and equitable treatment component in particular has become a source of significant controversy due to its record as the most frequently invoked standard of protection in investor-state arbitral disputes. Given the indeterminacy of the standard's content, it is impossible to determine the coherence of the practice of nations with regard to the minimum standard of treatment. And despite its being a legal principle, the plain meaning of the minimum standard of treatment leaves considerable discretion to arbiters in considering just what is the minimum standard. International liability for violations of the minimum standard of treatment as developed and defined by arbitral tribunals can reasonably be expected to affect how domestic policy makers exercise their authority.