procedures and treaty bodies have acknowledged the imperative to collaborate in this field.154 The Special Rapporteur on extreme poverty recommends ‘a contemporary interpretation of existing obligations of international cooperation and assistance’ in order to move from an ‘outdated emphasis on tax sovereignty to a more modern conception of international tax cooperation in a globalised and interdependent world economy’.155 At the same time, she has remarked on how difficult it has been to reach international agreement on tax cooperation owing to powerful entrenched interests and the reluctance of states to cede any sovereignty on tax affairs. The CESCR and several special procedures, including the Independent Expert on the promotion of a democratic and equitable international order, have stressed that states should take concerted and coordinated measures against tax evasion globally as part of their domestic and extraterritorial human rights obligations, as well as their duty to protect people from third-party human rights violations, including by transnational corporations and other business enterprises.156 Moreover, some special procedures have called for upgrading the UN Tax Committee to an intergovernmental tax body as a way to provide a democratic and inclusive platform for discussing tax matters.157 2.4 Concluding observations The present chapter reviewed the way that treaty bodies and special procedures have interpreted the legal basis of resource mobilisation obligations, as well as the principles that should guide them. Yet, the content of some of these legal obligations is complex and subject to disagreement. Moreover, the practical application of principles that should guide resource mobilisation have yet to be examined in any depth. Obligations related to progressive realisation, international assistance and cooperation, the prohibition on deliberately retrogressive measures and key concepts, such as ‘maximum available resources’ and ‘minimum core content’, remain elusive. The lack of a clear understanding of these obligations and concepts poses several challenges to human rights monitoring bodies seeking to assess compliance with rights realisation-related resource mobilisation obligations. How can they evaluate state responses in terms of compliance with the obligation to mobilise resources if the legal foundation of such obligations are themselves not clear? What are the criteria to assess whether or not a state has done all that it can to mobilise resources? How much effort should a state be required to take to mobilise and administer resources for human rights-consistent outcomes? 154 ‘Report of the Independent Expert on foreign debt, Juan Pablo Bohoslavsky’ (2016) UN Doc A/HRC/31/60, para 64; ‘Report of the Special Rapporteur on poverty, Magdalena Sepúlveda Carmona’ (2014) UN Doc A/HRC/26/28. See also, CESCR General Comment No 24 on State Obligations under the International Covenant on Economic, Social and Cultural Rights in the Context of Business Activities (2017). 155 ‘Report of the Special Rapporteur on poverty, Magdalena Sepúlveda Carmona’ (2014) UN Doc A/HRC/26/28, para 35. 156 See, eg, CESCR General Comment No 24; ‘Report of the Special Rapporteur on poverty, Magdalena Sepúlveda Carmona’ (2014) UN Doc A/HRC/26/28; ‘Report of the Independent Expert on international order, Alfred de Zayas’ (Preliminary views on the conceptual and legal framework of the mandate) (2012) UN Doc A/HRC/21/45. 157 See, eg, ‘Report of the Special Rapporteur on poverty, Magdalena Sepúlveda Carmona’ (2014) UN Doc A/HRC/26/28; ‘Reports of the Independent Expert on international order, Alfred de Zayas’ (2012) UN Doc A/HRC/21/45 and (2016) A/71/286, para 54. 48 The Obligation to Mobilise Resources: Bridging Human Rights, Sustainable Development Goals, and Economic and Fiscal Policies   December 2017