Consider where the law of foreign investment has been not only for the last twenty-five years but the last fifty, from the time when Western imperialism expired and the ranks of capital-importing independent States expanded essentially from Latin America to include Asia and Africa.

If we recall the constellation of countries circa 1960, there was a legal as well as economic gulf between capital-exporting States and capital-importing States. There was a great gulf on the substance of the governing international law – if any. There was a great gulf on international legal process – if any.

The depth of that gulf was certified by the Supreme Court of the United States in the Sabbatino case when it observed in 1964 that: “There are few if any issues in international law today on which opinion seems to be so divided as the limitations on a state's power to expropriate the property of aliens.”

On one side of that divide, capital exporters expounded a minimum standard in customary international law for the treatment of aliens and their property. They could not be denied justice; they were entitled not merely to national treatment but to a minimum standard of treatment that included observance of contracts and, in the event of a taking of their investments, prompt, adequate and effective compensation.