provided goods and services (“reciprocity”);<sup>25</sup> and (d) the governments administering those tax systems are accountable to taxpayers (“accountability”).<sup>26</sup> Most research to date has focused on the potential for expanded trust to increase broader tax morale, which would drive expanded “quasi-voluntary” tax compliance. Tax morale reflects individual ethics and values, social norms, and the extent of trust in tax systems, with the latter offering the most immediate target for prospective reformers. Research in this area initially came overwhelmingly from OECD countries, but has rapidly expanded in developing countries, and is reaching similar conclusions.<sup>27</sup> Trust and tax morale have great potential to expand political support for reforms, given the common deep distrust between taxpayers and tax authorities.<sup>28</sup> In OECD countries, the need to facilitate compliance is often the primary barrier to improved tax collection. By contrast, in most developing countries it is increasingly accepted that the most important barriers to collection are frequently political – that is, reform is not only about identifying strategies to encourage taxpayer compliance, but about identifying strategies that are politically feasible and mobilizing necessary political support for their implementation. This growing attention to political constraints is rooted in evidence that across the developing world there are immediate reform opportunities available, which have been consistently frustrated despite being both low cost and technically straightforward. For example, many governments fail to engage in even basic data sharing within tax administrations to identify the most obvious and egregious examples of tax evasion by elite groups – despite clear evidence that such data sharing can yield immediate gains.<sup>29</sup> A lack of political will emerges as the most compelling explanation.

The increasingly-recognized centrality of politics in bringing about tax reforms is consistent with its role in other aspects of public sector performance. The World Development Report (WDR) 2017, _Governance and the Law,_ argues that asymmetries of power—which lead to exclusion, capture, and clientelism—lie at the root of a wide range of development challenges. Tax reform inevitably creates winners, losers, and confronts strong vested interests. It cannot succeed without political support—but broad-based political support is frequently absent owing to perceptions that the system is unfair, and to the absence of clear reciprocity and benefits from expanded tax

> 25 Cummings, R. G., Martinez-Vazquez, J., McKee, M., & Benno, T. (2009). Tax morale affects tax compliance: Evidence from surveys and artefactual field experiment. _Field Experiments in Economics_ , 70 (3):447-457.

> 26 Alm, J., Jackson, B., & McKee, M. (1993). Fiscal exchange, collective decision institutions, and tax compliance _. Journal of Economic Behavior and Organization_ 22: 285–303.

> 27 Lago-Peñas, I., & Lago-Peñas, S. (2010). The determinants of tax morale in comparative perspective: Evidence from European countries. _European Journal of Political economy_ , 26(4), 441-453; Torgler, B. (2005). Tax morale in Latin America. _Public Choice_ , 122(1-2): 133-157; Chan, H. F., Supriyadi, M. W., & Torgler, B. (2017). Trust and tax morale. In _The Oxford Handbook of Social and Political Trust_ . Oxford University Press; NESG. (2019). A survey of Nigerian households and small businesses: What do Nigerians think about taxes? Lagos: The Nigerian Economic Summit Group.

> 28 Torgler, B. (2003). Tax morale, rule-governed behaviour and trust. _Constitutional Political Economy_ , 14(2):119-140.

> 29 Kangave, J., Nakato, S., Waiswa, R, & Lumala Zzimbe, P. (2016). Boosting revenue collection through taxing high net worth individuals: The case of Uganda. _ICTD Working Paper 45_ . Brighton: International Centre for Tax and Development; Kangave, J., Nakato, S, Waiswa, R, Nalukwago, M, & Lumala Zzimbe, P. (2018). What can we learn from the Uganda Revenue Authority's approach to taxing high net worth individuals? _ICTD Working Paper 72_ . Brighton: International Centre for Tax and Development; Moore, M, & Prichard, W. (2018). Tax reform for low-income countries: Five ideas for simplifying tax systems to fit local realities. _ICTD Summary Brief 17_ . Brighton: International Centre for Tax and Development.

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