The emergence of investor-state arbitration was based on perceived dependence of national court of the host state. But investor-state arbitration also has its systemic deficiencies in respect of guaranteeing procedural fairness. Investment treaty arbitration is not itself a treaty, but falls in sui generis category, within the domain of domestic law. Hence, national court of the host state retains the power of restraining an abuse of the international treaty arbitration according to domestic law and good faith which is a general principle of international law. But the exercise of such power should not undermine the rationale of investor-state arbitration. Judgement of India v. Vodafone represents the conflicts and coordination of domestic law and international law, and remarkable national practice of coordinating fragmented investment treaty arbitrations.