In a constitutional system such as that of the United States, a power that is vested in the President is best described as being which of the following?

Introduction / Context:
In constitutional democracies like the United States, powers of public offices are defined and limited by the written Constitution. The President is the head of the executive branch and exercises powers such as vetoing legislation, appointing officials, and acting as commander in chief. This question asks you to identify the best way to describe a power that is vested in the President within such a system.

Given Data / Assumptions:

• We are considering a system like that of the United States, where the President's powers are enumerated.
• The term vested suggests that the power is formally assigned.
• Options contrast sources of authority such as the Constitution, the Supreme Court, the House, the Senate, and informal custom.
• We assume basic understanding of separation of powers and written constitutions.

Concept / Approach:
In the United States, the Constitution is the supreme law of the land. Article two of the United States Constitution vests the executive power in the President and lists many of the President's specific powers. While the Supreme Court interprets the Constitution and may rule on disputes, it does not itself grant or guarantee presidential powers; it only clarifies how the Constitution applies. Similarly, although some presidential actions require Senate confirmation or House participation, the basic existence of the powers comes from the Constitution, not from those bodies. Therefore, the best description is that a power vested in the President is legally guaranteed by the Constitution.

Step-by-Step Solution:
Step 1: Identify that the phrase vested in the President refers to formal constitutional assignment of powers. Step 2: Recall that in the United States, the Constitution is the primary legal source of governmental powers and limitations. Step 3: Observe that the Supreme Court cannot create presidential powers; it only interprets the Constitution and statutes. Step 4: Recognise that while some presidential actions involve the House or Senate, the underlying powers are not simply granted by them but by the Constitution itself. Step 5: Select legally guaranteed by the Constitution as the correct option.

Verification / Alternative check:
Examining the text of the United States Constitution shows that presidential powers such as veto, appointment, treaty making, and command of the armed forces are stated in Article two and other sections. Legal commentators explain that these powers are constitutional grants and that any law or practice inconsistent with the Constitution can be struck down by courts. This confirms that the Constitution, not another institution, is the ultimate legal foundation of presidential power.

Why Other Options Are Wrong:
Legally guaranteed by the Supreme Court: The Supreme Court interprets the Constitution but does not itself grant powers; it may limit or clarify them. Subject to approval by the House of Representatives or the Senate: Some specific actions, such as treaty ratification or appointments, require Senate participation, and some legislative proposals involve the House, but the core powers are not defined as being granted by these bodies. Informal and based only on custom: While some practices are based on tradition, the phrase vested in the President refers to powers rooted in the written Constitution.

Common Pitfalls:
A frequent error is to overstate the role of the Supreme Court and assume that it is the source of presidential powers because it is the final interpreter of the Constitution. Another pitfall is to confuse procedural approvals, like Senate confirmation, with the source of authority. Understanding that a written constitution is the fundamental legal document that vests powers and that courts, legislatures, and executives operate within that framework is central to answering such questions correctly.

Final Answer:
Legally guaranteed by the Constitution