Primer on Separation of Powers, Inquiry in Aid of Legislation

There are three branches of the government — legislative, executive and judicial. Each department of the government has exclusive cognizance of the matters within its jurisdiction, and is supreme within its own sphere. But it does not follow from the fact that the three powers are to be kept separate and distinct that the Constitution intended them to be absolutely unrestrained and independent of each other. The Constitution has provided for an elaborate system of checks and balances to secure coordination in the workings of the various departments of the government.

Separation of Powers - Inquiry in Aid of Legislation, Executive Privilege, Question Hour


Broadly defined, the power of oversight embraces all activities undertaken by Congress to enhance its understanding of and influence over the implementation of legislation it has enacted. Clearly, oversight concerns post-enactment measures undertaken by Congress: (a) to monitor bureaucratic compliance with program objectives, (b) to determine whether agencies are properly administered, (c) to eliminate executive waste and dishonesty, (d) to prevent executive usurpation of legislative authority, and (e) to assess executive conformity with the congressional perception of public interest. The power of oversight has been held to be intrinsic in the grant of legislative power itself and integral to the checks and balances inherent in a democratic system of government.


The acts done by Congress purportedly in the exercise of its oversight powers may be divided into three categories, namely: (1) supervision, which connotes a continuing and informed awareness on the part of a congressional committee regarding executive operations in a given administrative area; (2) scrutiny, primarily intended to determine economy and efficiency of the operation of government activities, exercised through budget hearings, the “question hour” and the power of confirmation; and (2) investigation, which is also known as the “inquiry in aid of legislation”.


The Congressional power of inquiry is expressly recognized in Section 21 of Article VI of the Constitution:

SECTION 21. The Senate or the House of Representatives or any of its respective committees may conduct inquiries in aid of legislation in accordance with its duly published rules of procedure. The rights of persons appearing in or affected by such inquiries shall be respected.

Even without this express Constitutional provision, the power of inquiry is inherent in the power to legislate. The power of inquiry, with process to enforce it, is grounded on the necessity of information in the legislative process. If the information possessed by executive officials on the operation of their offices is necessary for wise legislation on that subject, by parity of reasoning, Congress has the right to that information and the power to compel the disclosure thereof.


Under the separation of powers, Congress has the right to obtain information from any source — even from officials of departments and agencies in the executive branch. It is this very separation that makes the congressional right to obtain information from the executive so essential, if the functions of the Congress as the elected representatives of the people are adequately to be carried out.


Members of the Supreme Court are exempt from this power of inquiry on the basis not only of separation of powers but also on the fiscal autonomy and the constitutional independence of the judiciary.


The power of legislative inquiry may be the subject of judicial review pursuant to the Supreme Court’s certiorari powers under Section 1, Article VIII of the Constitution. Since the right of Congress to conduct an inquiry in aid of legislation is, in theory, no less susceptible to abuse than executive or judicial power.


The President, on whom executive power is vested, is beyond the reach of Congress, except through the power of impeachment. It is based on the President’s position as the highest official of the executive branch, and the due respect accorded to a co-equal branch of government which is sanctioned by a long-standing custom.


The power of inquiry is broad enough to cover officials of the executive branch. The power of inquiry is co-extensive with the power to legislate. The matters which may be a proper subject of legislation and those which may be a proper subject of investigation are one. It follows that the operation of government, being a legitimate subject for legislation, is a proper subject for investigation. Since Congress has authority to inquire into the operations of the executive branch, it would be incongruous to hold that the power of inquiry does not extend to executive officials who are the most familiar with and informed on executive operations.


As contained in the 1987 Constitution (Section 21, Article VI), the power of Congress to investigate is circumscribed by three limitations, namely: (a) it must be in aid of its legislative functions, (b) it must be conducted in accordance with duly published rules of procedure, and (c) the persons appearing therein are afforded their constitutional rights, including the right to be represented by counsel and the right against self-incrimination.

In addition, even where the inquiry is in aid of legislation, there are still recognized exemptions to the power of inquiry, which exemptions fall under the rubric of executive privilege.


Executive privilege is not a clear or unitary concept, although it has been defined as “the power of the Government to withhold information from the public, the courts, and the Congress” or “the right of the President and high-level executive branch officers to withhold information from Congress, the courts, and ultimately the public.”


The matters covered under “executive privilege” include:

  • (1) Information between inter-government agencies prior to the conclusion of treaties and executive agreements;
  • (2) Presidential conversations, correspondences, and discussions in closed-door Cabinet meetings; and
  • (3) Matters affecting national security and public order.

Executive privilege is properly invoked in relation to specific categories of information and not to categories of persons. Executive privilege, whether asserted against Congress, the courts, or the public, is recognized only in relation to certain types of information of a sensitive character.


When an official is being summoned by Congress on a matter which, in his own judgment, might be covered by executive privilege, he must be afforded reasonable time to inform the President or the Executive Secretary of the possible need for invoking the privilege. This is necessary in order to provide the President or the Executive Secretary with fair opportunity to consider whether the matter indeed calls for a claim of executive privilege. If, after the lapse of that reasonable time, neither the President nor the Executive Secretary invokes the privilege, Congress is no longer bound to respect the failure of the official to appear before Congress and may then opt to avail of the necessary legal means to compel his appearance.


A claim of privilege, being a claim of exemption from an obligation to disclose information, must be clearly asserted. An implied claim of privilege is invalid per se. The validity of claims of privilege must be assessed on a case to case basis, examining the ground invoked therefore, and the particular circumstances surrounding it.


In the context of a parliamentary system of government, the question hour is a period of confrontation initiated by Parliament to hold the Prime Minister and the other ministers accountable for their acts and the operation of the government, corresponding to what is known in Britain as the question period. The framers of the 1987 Constitution removed the mandatory nature of such appearance during the question hour in the present Constitution so as to conform more fully to a system of separation of powers. This is provided in Article VI, Section 22 of the Constitution:

SECTION 22. The heads of departments may upon their own initiative, with the consent of the President, or upon the request of either House, as the rules of each House shall provide, appear before and be heard by such House on any matter pertaining to their departments. Written questions shall be submitted to the President of the Senate or the Speaker of the House of Representatives at least three days before their scheduled appearance. Interpellations shall not be limited to written questions, but may cover matters related thereto. When the security of the State or the public interest so requires and the President so states in writing, the appearance shall be conducted in executive session.


No. Section 21 (inquiry in aid of legislation) and Section 22 (question hour) of Article VI of the Constitution are closely related and complementary to each other, but they do not pertain to the same power of Congress. One specifically relates to the power to conduct inquiries in aid of legislation, the aim of which is to elicit information that may be used for legislation, while the other pertains to the power to conduct a question hour, the objective of which is to obtain information in pursuit of the oversight function of Congress. While attendance was meant to be discretionary in the question hour, it was compulsory in inquiries in aid of legislation.


This is tackled by the Supreme Court in Arnault vs. Nazareno, where the petitioner argued that the Senate lacks authority to commit him for contempt for a term beyond its period of legislative session. According to the Supreme Court:

That investigation has not been completed because of the refusal of the petitioner as a witness to answer certain questions pertinent to the subject of the inquiry. The Senate has empowered the committee to continue the investigation during the recess. By refusing to answer the questions, the witness has obstructed the performance by the Senate of its legislative function, and the Senate has the power to remove the obstruction by compelling the witness to answer the questions thru restraint of his liberty until he shall have answered them. That power subsists as long as the Senate, which is a continuing body, persists in performing the particular legislative function involved. To hold that it may punish the witness for contempt only during the session in which investigation was begun, would be to recognize the right of the Senate to perform its function but at the same time to deny to it an essential and appropriate means for its performance. Aside from this, if we should hold that the power to punish for contempt terminates upon the adjournment of the session, the Senate would have to resume the investigation at the next and succeeding sessions and repeat the contempt proceedings against the witness until the investigation is completed-an absurd, unnecessary, and vexatious procedure, which should be avoided.

As against the foregoing conclusion it is argued for the petitioner that the power may be abusively and oppressively exerted by the Senate which might keep the witness in prison for life. But we must assume that the Senate will not be disposed to exert the power beyond its proper bounds. And if, contrary to this assumption, proper limitations are disregarded, the portals of this Court are always open to those whose rights might thus be transgressed.

[Sources: Senate of the Philippines vs. Eduardo R. Ermita, G.R. No. 169777, 20 April 2006; Angara vs. Electoral Commission, G.R. No. L-45081, 15 July 1936; Arnault vs. Nazareno, G.R. No. L-3820, 18 July 1950; Bengzon vs. Senate Blue Ribbon Committee, G.R. No. 89914, 20 November 1991; Concurring and dissenting opinion of Justice Puno in Macalintal vs. COMELEC, G.R. No. 157013. July 10, 2003]

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7 thoughts on “Primer on Separation of Powers, Inquiry in Aid of Legislation

  1. AvatarLea V

    Atty. Fred;

    Sir, most local legislative bodies like the Sangguniang Bayan think that when they request for the attendance of municipal officers from the executive depts, it is compulsory for them to attend because it is always in aid of legislation, even if in truth their concerns are more for the furtherance of their oversight functions. Can these executive officers validly excuse themselves from attending because in the local level, the powers established under Sections 21 and 22 also apply in the municipal setting? Thank you.

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