Fornier vowed to persuade the Commission on Elections (Comelec) to reverse its decision on his petition questioning Poes citizenship and seeking the actors disqualification from the presidential race.
He said he intends to file a motion for reconsideration with the Comelec at noon tomorrow.
"We will raise point-by-point the basis why Poe should be disqualified from the elections," Fornier told reporters.
He maintained that there was nothing personal in his petition against Poe, who has been consistently topping popularity surveys.
Fornier added that the disqualification case against Poe "will be for his own benefit," pointing out that the issue will no longer haunt Poe if he is elected and proclaimed president.
Last Friday, Poe scored a major victory when the Comelec dismissed Forniers petition for lack of merit, ruling that Poe is a natural-born Filipino citizen eligible to run for president.
Fornier earlier said that he will bring the case to the Supreme Court (SC) if the Comelec does not reverse its decision.
In his petition, Fornier contended that Poe is not a natural-born Filipino citizen because his father was a Spanish subject and his mother was an American. He claims that Poe was an illegitimate child and argues that illegitimate children must take their mothers citizenship.
The Comelecs first division rejected Forniers arguments and ruled that Poes father, Allan Fernando Poe, was a Filipino despite his Spanish heritage.
"Legitimacy therefore is beside the point. As long as the father is a Filipino, the child will always be a Filipino," said the decision.
The Comelec said Spanish citizens had the option to retain their citizenship when Spain ceded the Philippines to the United States under the Treaty of Paris in 1898.
But Poes grandfather, Lorenzo Pou, did not elect to retain his Spanish citizenship and should be considered a Filipino citizen.
The poll body said Fornier should have presented proof that Lorenzo Pou intended to retain his Spanish citizenship though a declaration of allegiance to Spain before a court of record.
"Since there was no such declaration, he should be held to have adopted the nationality of the territory in which he resides," the Comelec said.
Last Friday, a group of private lawyers asked the SC yesterday to nullify the Comelecs decision to recognize the presidential candidacy of Poe on the basis that Poe is not a natural-born Filipino citizen, but actually an American.
Lawyers Maria Jeannette Tecson, Felix Desiderio Jr. and Gertrudo de Leon said the Comelec acted with "grave abuse of discretion" when it heard the petition questioning the citizenship of Poe, since it lacked jurisdiction over the matter.
The petitioners also said the Comelec should be stopped from recognizing Poes candidacy. They asked the SC to order the permanent removal of Poe as a qualified candidate for president in all records of the Comelec.
In a 19-page petition, the three lawyers asked the SC to assume jurisdiction over the question on Poes citizenship, since it has the sole jurisdiction to resolve matters relating to the qualifications of presidential candidates.
Tecson, Desiderio and De Leon said Poe should be disqualified, since his own records show he is an illegitimate child who, under the law, should have adopted the nationality and surname of his American mother, Bessie Kelley.
The three lawyers said Poe was illegitimate because he was born out of wedlock. His parents, Allan Fernando Poe and Kelley, married on Sept. 16, 1940 a little over a year after he was born on Aug. 20, 1939.
Since the marriage contract of his parents showed Poes mother was American, Poe, therefore, is also an American, they said. Philippine laws state that an illegitimate child takes on the citizenship of his or her mother.
The three lawyers said allowing Poe to run "will not only work to continue misleading the voting public on Poe, but will more importantly cause heightened emotions, grave and irreparable damage to the Philippines because a foreign national is being allowed to vie for the highest position in the executive branch of government."
The petitioners said Poes parents failed to comply with the requirements to legitimize him based on the provisions of the Old Civil Code. They said there should be a public instrument executed to acknowledge Poe as the true son of his father.
But, even if he were legitimated, the three lawyers said, Poe will still not be qualified to run for president because he is not a natural-born Filipino citizen.
Under the 1987 Constitution, natural-born Filipinos are citizens of the Philippines from birth, without having to perform any act to acquire or perfect their Philippine citizenship.
This refutes the claim that Poe is a legitimate child of his parents and is a natural-born Filipino entitled to all the rights of a legitimate child including the acquisition of his fathers citizenship.