Legislative inquiries and oversight functions, Constitutional Law

1. Legislative inquiries

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. (Section 21, Article VI, 1987 Constitution)

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. (Section 22, Article VI, Ibid.)

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. (Ibid.)

a. Via a Committee of either Chamber of a Congress

Once an inquiry is admitted or established to be within the jurisdiction of a legislative body to make, the investigating committee has the power to require a witness to answer any question pertinent to that inquiry, subject of course to his constitutional right against self-incrimination. (Arnault v. Nazareno, En Banc, G.R. No. L-3820, 18 July 1950)

If the subject...