Final answer:
Presidents have trouble getting things done because other policy makers have their own agendas and powers. Presidents can set the policy agenda, lobby Congress, make policies through appointments and executive orders, and use their position to gain public approval.
Step-by-step explanation:
Presidents have trouble getting things done because other policy makers with whom they deal have their own agendas, interests, and sources of power. Presidents hold a ceremonial position as head of state, but they also have powers and prerogatives that offer opportunities for leadership. They can set the policy agenda, lobby Congress, make policies through appointments and executive orders, and use their position to gain public approval.