What does this have to do with tax? If norms are agreed to between two states in a bilateral agreement, and these norms are transgressed by domestic tax legislation, the opportunity arises for the offended foreign investing party to approach their state to invoke diplomatic protection and hold the offending state that they are investing into responsible for any harm that they may have suffered. Even after they have exhausted normal court channels in the offending state and lost. The offending state is held responsible for its courts' actions, where the obligation transgressed by the offending state is contrary to international law norms - what is contained in the treaty. On 16 July 2008, the US Trade Representative and the SACU Trade Ministers signed a Trade and Investment Development Cooperation Agreement. The TIDCA is meant to be a stepping stone to a full FTA, so the process is still in motion.
The US began negotiating a free trade agreement with the Southern African Customs Union — composed of South Africa, Botswana, Namibia, Lesotho and Swaziland — in June 2003. The talks first got stalled in mid-2004, largely because of the US’ extreme and inflexbile demands regarding intellectual property rights. Around July-September 2005, officials started trying to reignite the process by chopping the FTA negotiating items into "bite size pieces". By early 2006, the process was looking like it would still go nowhere and in April that year it was suspended. From the start, the prospects of a US-SACU accord raised a lot of fears in the subregion, if past US free trade agreements are anything to go by. The demands put forward by the US — especially in terms of investment and intellectual property, including patents on drugs and seeds — would be quite radical for the SACU countries. While the talks were stalled, the US administration reportedly began looking into the possibility of negotiating bilaterals FTAs with individual sub-Saharan African countries. Washington also proposed that the US and SACU adopt a Trade and Investment Cooperation agreement — more than a TIFA, but less than an FTA — as step towards a full-fledged FTA. On 16 July 2008, the US Trade Representative and the SACU Trade Ministers signed a Trade and Investment Development Cooperation Agreement. The TIDCA is meant to be a stepping stone to a full FTA, so the process is still in motion.