The notion of due diligence is not usually included among the standards of treatment and protection of investments, but still plays a role in determining whether such standards have been violated by a host State or by an investor. Although not a stand-alone treaty standard, it is of considerable importance in interpreting some of the key standards, such as the International Minimum Standard or the Full Protection and Security Standard.The concept applies also in international investment law to the examination of whether the State has acted with due diligence or vigilance in addressing the question of State responsibility for damage caused by the conduct of private persons.
Therefore, if the State demonstrates that it has taken appropriate measures, it avoids international responsibility.