232. In adopting the judicial approach to EDR systems, it is desirable that the judicial bodies entrusted with resolving electoral challenges (both the body with the authority to issue the final decision of judgement, and any other body which forms at least one of the prior mechanisms involved in considering challenges) should have at least three members. This is particularly important for the highest level body of the EDRS, as it helps to ensure the guarantees of independence and impartiality inherent to that body and its members individually, in addition to providing other personal guarantees, such as responsibility and accountability. 3. Guiding principles for EDRBs and the design of structural guarantees to entrench them 233. One fundamental aspect of electoral justice is thus the design of what are called ‘structural guarantees’ or ‘judicial guarantees’, which are those legal instruments for ensuring that the bodies entrusted with EDR systems can act independently in relation to all other government bodies, political parties and other electoral stakeholders. This is essential if the EDRBs are to be able to resolve the cases put to them objectively and impartially on the basis of the merits of the case. 234. These structural or judicial guarantees are designed especially for judicial EDRBs (whether these are regular, constitutional, administrative or specialized electoral courts). It is also advisable, to the extent possible, to provide for such guarantees in other types of EDRB, whether it is an EMB or an international, ad hoc or even legislative body (when the corresponding EDRS combines final decision by the legislative body with a prior challenge before a judicial body). This is intended to ensure that such bodies will resolve the challenges under their jurisdiction with functional independence and impartiality and in keeping with the law. This is more difficult in principle in the case of legislative bodies or governmental EMBs, but if they are entrusted with part of the EDRS they should still demonstrate their functional independence and impartiality for the sake of the legitimacy and credibility of the system even though in general they do not embody all the guarantees analysed below. EDR systems entrusted to specialized electoral courts incorporate more of these guarantees. 235. Structural or judicial guarantees embody the guiding principles of EDR. These include, among others, legal recognition of the independence of the EDRB, and of the independence and impartiality of its members; a regime for accountability and liability of the EDRB; the integrity and professionalism of EDRB members; and the financial autonomy and sustainability of the EDRB (see box 6.1). In this respect, chapters 4, 6 and 7 of Electoral Management Design: The International IDEA Handbook are a useful reference point: many of the principles and guarantees relating to EMBs that are analysed there are also applicable to the design of EDRBs. 88