The Trans-Pacific Partnership Agreement and States’ Right to Regulate Under International Investment Law

The Trans-Pacific Partnership Agreement (‘TPP'), which was signed in November 2015 by the United States, Japan, Canada, Mexico, Peru, Chile, Brunei, Malaysia, Singapore, Australia, New Zealand, and Vietnam, is arguably the most significant trade and international investment protection deal since the creation of the European single market. The TPP was intended to establish a free trade area in the Asia-Pacific that accounts for nearly 40 percent of global GDP and a third of global trade. While the TPP was eventually not ratified following the U.S. administration's announcement in January 2017 that it will not ratify the treaty, the other original TPP signatories concluded the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (‘CPTPP'), which adopted the most of the TPP's provisions.The politics of the widespread skepticism towards the TPP and other international investment agreements (‘IIAs') is complex and widely debated. This article focuses on one issue that has played an important role in framing the debate on the TPP: the potential impact of the TPP on States' right to regulate for the public welfare under international investment law.The article concludes that the TPP's Investment Chapter is evolutionary in its approach to foreign investment protection, and continues the recent trend in IIA practice to include language intended to safeguard host States' legitimate public welfare objectives. Although the TPP's Investment Chapter may not be radical, its provisions arguably reinforce the legal foundation for States' right to regulate for the public welfare without incurring liability under international investment law. This may not, however, be enough to satisfy increasingly skeptical politicians and citizens of the merits of ratification