In recent presidential administrations, what has comprised the principal staff for the President?

The White House Office is the principal staff for the President, and it plays a crucial role in the administration's operations. This office consists of key advisors, assistants, and staff who are directly employed by the President and are integral to the decision-making process. The members of the White House Office, including the Chief of Staff and various advisors, focus on the day-to-day management of presidential tasks and help shape policy and strategy. Their proximity to the President allows for immediate communication and swift action on important issues.

In contrast, while the Cabinet is composed of the heads of the executive departments and offers significant advice on departmental matters, it does not function in the same immediate capacity as the White House Office. Congress, while essential to the legislative process, is not part of the executive branch's staff and does not directly assist the President in the day-to-day execution of policies. The national committee of the President's party plays a role in electoral strategies and party organization, but it is not considered part of the President's principal staff.