Secondly, I will show how WTO rules and laws on direct taxation can intervene and how they have interfered in the past. I will highlight the different ways in which such interventions can occur, as well as the main comparisons before the DSB in terms of direct taxation. The principle of the NTs of Gatt Articles III, Article XVII of the GATS and Article 3 of the TRIPS Agreement prevents WTO Members from treating nationals of other Member States less than their own nationals.  Just as the most fiscal principle prohibits international taxation from distinguishing between cash flows from different WTO member states, the NT principle prevents member states from discriminating against their citizens and the citizens of other members through national taxes.  As noted above, the range of WTO rules has continued to expand. Among other things, this has led to more possible interference between these rules and direct tax laws. Some of these disruptions have already given rise to disputes before the DSB. However, the DSB has not taken a decision in all these cases and some possible interventions have not yet been submitted to the DSB. Finally, I would like to conclude whether these arguments justify the WTO regulating direct taxes or whether direct taxation should be completely exempted from WTO rules. Double taxation is not necessarily legislation that recognises cross-border trade. Rather, it may be the result of tax rules aimed exclusively at national economic measures.
However, as noted above, these measures may have a prohibitive effect on cross-border investments. Tax exemptions, on the other hand, attract foreign investment. Both effectively lead to different treatment between the inhabitants of countries and those of other states. For all the above reasons, the WTO could not effectively advance its objectives while having no competence in the field of direct taxation. From a legal point of view, direct taxes can be included in WTO rules. Originally, Member States did not intend for gatt or WTO to rule on direct taxes. However, over time, WTO members have accepted the WTO`s jurisdiction in this area. They demonstrated this not only by recognising the WTO`s competence in direct taxation, but also by explicitly mentioning direct taxation in the SCM Agreement. Moreover, the very basis of the WTO treaties is the principle of non-discrimination.
As noted above, measures taken in direct tax law may lead to legal discrimination. From a purely legal point of view, for example, the prevention of discrimination argues in favour of including direct taxation in WTO rules. The GATS excludes certain areas of direct taxation from WTO jurisdiction, but generally allows the WTO to rule on direct taxation issues in order to advance its objectives of efficient world trade. Finally, under the SCM Agreement, member states have expressly conferred on the WTO the legal power to decide on direct taxation. .