Castillo, a sister of LDP president Sen. Edgardo Angara, said the gathering of political forces to proclaim movie actor Fernando Poe Jr. (FPJ) today would finally settle the question on who should be the opposition standard bearer, effectively marginalizing Lacson.
"My personal assessment is that Senator Lacson will withdraw once FPJ is proclaimed as standard bearer," Castillo said.
She said FPJs camp within the LDP and other opposition parties will finally resolve the contest between the actor and the senator.
"FPJs proclamation is the key to unifying the opposition and resolving the internal problem in LDP," she said.
The congresswoman said Poe stands out as the overwhelming choice of the electorate based on surveys.
Castillo called for a stop to the bickering within the opposition to enable the parties to unite and further boost its chances of winning Malacañang next May.
Meanwhile, Maguindanao Rep. Didagen Dilangalen of the Partido ng Masang Pilipino (PMP), founded by deposed President Joseph Estrada, said his party will support Poe.
"We will support whoever President Estrada will endorse," Dilangalen said. "Its very clear who his candidate is and its FPJ."
Lacsons allies in the LDP, however, accused Angara of pushing Poe to run so that he can be the de facto president if the actor gets elected.
Deputy minority leader, Iloilo Rep. Rolex Suplico said this is obvious in the way Angara has been trying to manipulate Poe.
"Edong Angara wants to be president by proxy," Suplico said. "He (thinks) he can dictate to (Poe), but hes wrong. (Poe) is his own man."
Another Poe supporter and the actors unofficial spokesman, Sen. Vicente Sotto III said that Suplico has been dropped from the LDP by his own West Visayas partymates.