Final answer:
A president should have effective communication skills and strong foreign policy experience to carry out the duty of party chief. These qualifications enable the president to influence public opinion, legislation, and effectively represent the country, although the president's performance can also be affected by the broader political context.
Step-by-step explanation:
The qualifications a president should have to carry out the duty of party chief revolve primarily around their ability to influence public opinion and to sway legislation through the use of media and public messages. The role entails not just domestic but also significant foreign policy responsibilities. Effective communication skills are critical in this aspect, allowing the president to articulate policies clearly, mobilize support, and effectively represent the country on the world stage. A strong foreign policy experience is beneficial since the president acts as America's chief diplomat and is often the voice of the United States in international affairs. While a legal background and military service can be advantageous, they are not the primary qualifications for a president serving as party chief. Moreover, a president's performance and legacy are often influenced by factors such as the level of support from their party and the circumstances under which they came to office, which can impact their ability to realize ambitions, especially in the face of a hostile or divided Congress.