Final answer:
The national committee and its chair oversee the day-to-day operations of a political party's national organization, coordinating major events like the national convention and supporting candidates.
Step-by-step explanation:
The day-to-day operations of the political party's national organization are typically overseen by the national committee and its committee chair. During presidential election seasons, the national committee and the chair are specifically responsible for coordinating the grand political spectacles such as the national convention, which not only marks the formal nomination of the party's presidential and vice-presidential candidates but also signifies a crucial pivot from the primary to the general election. Furthermore, the national organization plays a pivotal role in fundraising, supporting candidates, and drafting the party's platform, which lays out its policy positions and goals.