The Senate majority includes Senate President Pro Tempore Juan Flavier, Senate Majority Leader Francis Pangilinan, Villar and Senators Joker Arroyo, Ramon Magsaysay Jr., Rodolfo Biazon and Ralph Recto.
Incoming administration senators include Senate race topnotcher Mar Roxas, Ramon Revilla Jr., Richard Gordon, Pia Cayetano, Miriam Defensor-Santiago and former Pampanga Gov. Lito Lapid.
The minority bloc in the Senate is composed of Senators Edgardo Angara, Panfilo Lacson, Sergio Osmeña III, Aquilino Pimentel Jr., Luisa "Loi" Ejercito and Senators-elect Jose "Jinggoy" Estrada, Jamby Madrigal, Juan Ponce Enrile and Alfredo Lim.
Pimentel said a bloc of senators identified with Villar may challenge the leadership of Drilon when the 13th Congress convenes on July 25.
"I think the fight will be between Drilon and Villar," Pimentel said at a media forum.
Villars bid for the top Senate post was floated by his supporters even before the 12th Congress adjourned and convened as the National Board of Canvassers, he said.
Villar chairs the Senate foreign relations committee and served as Speaker of the House of Representatives when he served as congressman of Las Piñas.
He gained prominence for the pivotal role he played in the impeachment of ousted President Joseph Estrada in November 2000. Villar had caused the immediate transmittal of the articles of impeachment from the House to the Senate by reciting the transmittal non-stop, overriding the attempt of Maguindanao Rep. Didagen Dilangalen to stop the proceedings.
Villar is reportedly backed by the "Congress bloc," also known as the "Wednesday Group," in the Senate composed of Recto, Pangilinan and Arroyo.
Political observers in the Senate predicted that if Villar gets the support of the minority opposition bloc, he may oust Drilon from the helm of the Senate.
Pimentel said the opposition in the Senate lacks the numbers to challenge Drilons leadership in the 13th Congress and, thus, "the fight will be confined in the majority bloc, between Drilon and Villar."
Biazon, however, is of a different opinion, as he expressed confidence that Drilon will keep his post as Senate President in the 13th Congress.
"Senate President Drilon will stay in the Senate presidency," Biazon said, adding that Villar has not personally declared that he is interested in becoming Senate president.
"Senator Villar has not said that he is after the position," Biazon said. "I am not aware about Villars intention to contest with Drilon. There are those probably entertaining that (challenging Drilon for the Senate presidency) , but I think Drilons presidency (of the Senate) is stable and that he enjoys the support of the majority."
Biazon said the proclamation of Sen. Noli de Castro as vice president will not affect the work of the Senate and the numbers of the majority in the chamber, adding that there is no need to hold special elections for De Castros replacement.
"We will be 23 senators, with Senator De Castros election as vice-president. In the 12th Congress, we were only 22. So, it has no effect at all," Biazon said. "Having a special election for only one senator will cost billions. I dont think thats a matter to be addressed. Our role is to legislate, perform oversight functions, to educate the people, to provide a check and balance."
He also said there is no way the Commission on Elections (Comelec) would nullify his proclamation as the 12th senator-elect in the May 10 elections, despite the protest filed by outgoing Senators Robert Barbers and John Osmeña, both of whom ran with him for the Senate under the banner of the administration coalition.
Pimentel said he will concentrate on doing his job as a legislator and prioritize seeking a review of the absentee voting law.
He said the absentee voting law must be revised, as it contains flaws which may have contributed to the low turnout of voters. In some cases, no overseas voters cast their ballots.
Pimentel has begun meeting with overseas Filipino workers to determine the amendments that may be needed to improve the absentee voting law.