In political representation, an instructed delegate is a representative who acts according to the wishes of his constituents, while a trustee exercises his own judgment. The delegate model of representation often applies to situations in which the represented bodies are independent entities with conflicting interests. The trustee model of representation is the norm for representative bodies within a nation.
The delegate and trustee models of representation are highly contrasting. Delegates carry out instructions or orders from those whom they represent. They cast a vote or make a decision as their constituents would have them do, even when it conflicts with their private opinion. This representation is common in international relations, in which the political body represented is a sovereign nation or a government. Ambassadors and representatives to the United Nations, for example, do not shape treaties or cast votes as they wish, but as the president instructs. These situations are characterized by independent and competing states.
Trustees vote their conscience. Representatives at national legislatures tend to employ the trustee model. In these situations, the legislature or other deliberative body acts as the voice of a single nation. Although the representatives come from different states or provinces, their intention is not exclusively to further the interest of their constituency, but to achieve the collective good of the entire country.