Under the doctrine of separation of powers, the Congress (Senate and House of Representatives) cannot subpoena or compel the President to appear before it to answer an investigation conducted by any of its committees. If Congress cannot subpoena the President then the same should be applied to Vice President Jejomar Binay considering that the Office of the Vice President is regarded as a component of the Executive Department of the government. Hence, Binay could not be forced by the Senate Blue Ribbon Committee to appear before it in connection with its inquiry on the alleged overpricing of Makati City Hall II.
Binay has the option not to attend the hearing since only an “invitation” and not a subpoena was sent to him to appear in the investigation. The pendency of a plunder case against him before the Ombudsman which involves the same transaction further justifies his non-appearance in the Senate.
Also, any congressional investigation must strictly comply with the constitutional requirement that it is in “aid of legislation.” If the inquiry is merely “in the guise of as aid in legislation” then any subpoena by such committee could be refused, as enunciated by then Constitutional Comission delegate later Chief Justice Hilario Davide, Jr., in the 1986 ConCom deliberations.
Binay knows that it will be a political suicide to attend such investigation since it is now turning out to be a political show rather than an inquiry in aid of legislation. His detractors who are conducting the investigation had already said that there is “direct testimony” pointing to his alleged guilt – a prejudgment that practically denies him a fair and impartial hearing in the Senate.
But legally speaking, the testimonies of these witnesses could only be treated as “evidence” after giving Binay his lawful right to cross-examine the witnesses in a court of law which he could not do in the Senate as the same is not allowed in a congressional inquiry. His lawyer cannot even say a word before the committee but could only advise him in whispers. Thus, the testimonies of the said witnesses in the Senate will remain as mere allegations and not evidence, until and unless they have been subjected to a rigid cross examination which is the only means of testing their credibility and biases.
Atty. Romulo B. Macalintal is known to be the country’s foremost election lawyer. He is also a poet.
 Cited in a lecture of Chief Justice Reynato S. Puno on February 28, 2005 at the U.P. College of Law.