The senate has usually been fertile ground for the country's next crop of executive leaders and several of its 24 members might just be major players in next year's elections for the presidency and vice presidency.
Half of those speculated to throw their hat into the political ring in 2016 ultimately have nothing to lose, as they are in the middle of their terms and would return to the Senate if the odds do not fall in their favour.
Senators Alan Peter Cayetano, Miriam Defensor-Santiago, Ferdinand Marcos Jr. and detained Bong Revilla Jr. are among those considering the prospect of running for President in 2016. But whether or not they will push through with it remains to be seen. Revilla declared earlier that his incarceration will not stop his 2016 plans.
Neophyte Sen. Grace Poe has so far been less than categorical about her 2016 plans, but has been the subject of calls for her to seek higher office, which she said she would take into consideration.
Poe, who got most of the votes in the 2013 senatorial race, has been floated as a possible candidate for the presidency. She has also topped recent surveys for the electorate's preferred Vice President, and several possible team ups with her as Vice President have been broached.
Earlier, there was speculation that Poe might join forces with Sen. Francis Escudero, who has yet to disclose his 2016 plans, if any.
Sen. Antonio Trillanes has said he wants to run for Vice President, but would rather wait for his party's decision if it would choose to field him for this post.
Sen. Jose "Jinggoy" Estrada, also in detention like Revilla, is reportedly among those being considered to be the running mate of Vice President Jejomar Binay.
Of these possible candidates, Poe, Cayetano, Escudero and Trillanes are assured of keeping a government post once elections are over, since they have just come from securing their six-year Senate terms during the 2013 elections.
Santiago, Revilla and Estrada are among the "graduating" senators, or those coming to the end of their two consecutive terms. They are no longer allowed to run for another term in the Senate next year.
Marcos is about to complete his first six-year term and is eligible for another one. He would have to choose between seeking an executive post and a legislative one when he runs next year.
There are also other factors that could affect which senators would actually go ahead and run for top executive posts, not least of which are their rankings in the surveys, especially those conducted close to the date of the filing of certificates of candidacy.
Santiago is currently battling stage 4 lung cancer and chronic fatigue syndrome.
Estrada and Revilla are both in jail and facing plunder charges.
The configurations of the teams for the top two executive posts are still up in the air. There are several possible major players outside the Senate who have yet to make their move.
Binay's running mate, Roxas
Binay, the current topnotcher in surveys for the presidency, is still mulling over who to pick as his running mate.
Interior Secretary Mar Roxas is the presumptive standard-bearer of the ruling Liberal Party, though he has yet to categorically say if he would run in 2016.
Recently, a group of retired police and military officials called on former Sen. Panfilo Lacson Jr. to seek higher office, in tandem with Poe.
Joseph Estrada, Duterte
There have also been reports that former President Joseph Estrada, who failed to complete his first term after being ousted in a mass revolt, might consider running for president. Estrada, the incumbent Manila mayor, had said he would consider running if neither Binay nor Poe, the daughter of his friend Fernando Poe Jr., would seek the presidency.
Several groups have been clamoring for Davao City Mayor Rodrigo Duterte to join the race for Malacañang. His party, the PDP-Laban, is considering fielding him as its standard-bearer.
It also remains to be seen which political parties would coalesce or team up for the 2016 elections.
Political ties fluid
In the Philippines, political partnerships tend to be fluid. Parties or individuals who are at each other's throats one moment could be linking arms the next.
Also, party affiliations do not always matter greatly, since many politicians could change their colors at the drop of a hat and suffer no lasting consequences.
Moreover, if a politician refuses to join one group or another, he or she can just establish his or her own party.
Admin coalition, opposition
At present, the administration's Liberal Party is allied with the Nacionalista Party, the Nationalist People's Coalition, PDP-Laban and the Laban ng Demokratikong Pilipino.
But this alliance could dissolve next year when the major players position their candidates for the next round of political games.
The opposition party is the United Nationalist Alliance of Binay.
The Senate also has other graduating members, who have so far not hinted at any plans to run for top executive posts next year. They are Senators Juan Ponce Enrile, who is also detained for plunder, Pia Cayetano and Manuel "Lito" Lapid.
Lapid is reported to be eyeing a local post in Pampanga.
His son, Mark, Tourism Infrastructure and Enterprise Zone Authority chief operations officer, is reportedly running for the Senate.
The Cayetanos are also planning to field Taguig Rep. Lino Cayetano in next year's senatorial race.
Several of the incumbent senators are also eligible to run for a second consecutive term next year.
They are Senate President Franklin Drilon, Senate President Pro Tempore Ralph Recto, and Senators Vicente Sotto III, Sergio Osmeña III and Teofisto Guingona III.
Senators Loren Legarda, Cynthia Villar, Nancy Binay, Sonny Angara, JV Ejercito, Aquilino Pimentel III, Gregorio Honasan and Paolo Benigno Aquino IV are currently in the middle of their six-year terms they won in 2013, and have so far not been rumored to have plans to seek higher office.
Since 1998, the country's Presidents have all cut their teeth in the Senate before ascending to Malacañang.
Joseph Estrada, a popular actor and longtime San Juan mayor before he sought national office, became known as one of the members of the "Magnificent 12" senators who had voted to remove the US bases from the country.
Gloria Macapagal-Arroyo topped the 1995 senatorial elections and later successfully ran for Vice President. She eventually became President after Estrada's ouster in a mass uprising and won another term in 2004.
President Aquino was on his first term as senator when he chose to run for chief executive following a wave of public sympathy generated by the death of his well-loved mother, former President Corazon Aquino.