G.R. No. 106971 - Guingona, Jr. vs. Gonzales

The parties agreed on a mathematical formula to determine each party’s fractional entitlement to the Commission on Appointments:

Organization Meeting of the Senate and Formation of the Commission on Appointments

Senator Romulo, as Majority Floor Leader of the LDP, nominated eight senators for the Commission on Appointments.
The nominees from the LDP included Senators Angara, Herrera, Alvarez, Aquino, Mercado, Ople, Sotto, and Romulo himself.

Senator Teofisto Guingona, acting as Minority Floor Leader for LAKAS-NUCD, along with Senator John Osmena representing the NPC, objected to the nomination of the eighth LDP senator.
Senator Arturo Tolentino proposed a compromise to elect x number of members with the following arrangement: eight from LDP, two from NPC, and one each from LP-PDP-LABAN and LAKAS-NUCD.
Despite reservations by Senators Guingona and Osmena, the compromise was approved to enable the organization of the Commission.

On September 23, 1992, Senator Guingona, on behalf of LAKAS-NUCD, filed a petition for a writ of prohibition.
Grounds of the Petition:

It was argued that the compromise and the resulting election of Senator Romulo (LDP) and Senator Tanada (LP-PDP-LABAN) violated the rule of proportional representation.
The petition asserted that fractional representations (half seats) for certain parties, according to Section 18, Article VI of the 1987 Constitution, should not be converted into whole seats by simply summing halves.
It was contended that the method used by the LDP majority unduly increased its representation by “rounding up” fractional seats, thereby reducing the represented share of the minority parties (LAKAS-NUCD and NPC).

Section 18 of Article VI of the 1987 Constitution mandates the creation of a Commission on Appointments composed of:

The necessity for proportional representation in the Commission.
Precedents from cases such as Coseteng vs. Mitra, Jr. and earlier decisions that reinforce the strict interpretation of the proportionality requirement.

The petition also addressed the alternative grounds of mandamus, claiming that the minority parties were being deprived of their constitutionally entitled representation.

Constitutionality of the Election of Senators to the Commission on Appointments

Whether the election of Senators Alberto Romulo and Wigberto Tanada as members of the Commission on Appointments conforms with Section 18 of Article VI of the 1987 Constitution.

Whether the Senate, acting through its LDP majority, exceeded its jurisdiction by manipulating fractional memberships to confer additional whole seats.

Whether a writ of prohibition should be issued to enjoin Senators Romulo and Tanada from assuming and discharging the functions of Commission members.
Alternatively, whether mandamus relief should be granted to restore the minority parties’ proportional representation rights.