Final answer:
Members of Congress acting as delegates cast their votes based on the preferences of their constituents, following the delegate model of representation, while balancing various demands in practice.
Step-by-step explanation:
Members of Congress who adopt the delegate role of representation typically cast their votes based on the preferences of the majority of their constituents. This delegate model of representation suggests that legislators are primarily the voices of the people who elected them, and their duty is to enact the wishes of those constituents directly into legislative action. In contrast, representatives who adopt the trustee model use their own judgment to decide what is best for their constituents. However, the process is complex, and representatives often find themselves balancing different demands, including those of constituents, parties, and the nation as a whole, which is referred to as the politico model of representation.