MANILA, Philippines – The 1987 Philippine Constitution has made it clear that only those who are "natural-born citizens of the Philippines" can run for national elective positions.
Also, the Local Government Code says dual citizenship and permanent residency outside the country are grounds for disqualification of local elective officials.
That's why during an election season, issues on citizenship surface to discredit some candidates and potential poll contenders – the latest of which, is 2016 presidential contender Senator Grace Poe.
Poe admitted she used to hold dual citizenship, but stressed she renounced her US citizenship before she joined government – thus reverting to being a natural-born Filipino. (READ: Grace Poe: I'm a natural born Filipino citizen)
Other candidates in the past were faced with the same issue, and most of them were able to successfully prove their eligibility to participate in the elections and be elected to a post. Here are some of them:
Fernando Poe Jr
The lady senator's fate resembles that of his father, Fernando Poe Jr (FPJ), who faced the same issue when he ran for president in 2004.
A disqualification case was filed against FPJ, claiming that the actor-turned-candidate acquired the citizenship of his American mother at birth because his father – a Spanish-turned-Filipino citizen – did not acknowledge him in his birth certificate.
In March 2004 – two months before the polls – the Supreme Court (SC) favored FPJ's candidacy. (READ: FPJ's citizenship woes a glimpse of Grace Poe's battle ahead)
The results of the poll didn't favor Poe, however, as he lost to then incumbent president Gloria Macapagal-Arroyo with just a small margin.
Just like Poe, Manzano also failed to snatch a national elective post, as he ran but lost in the 2010 vice presidential elections.
But before his failed vice presidential bid, he actually ran for vice mayor of Makati City in 1998 and won.
His victory, however, didn't come uncontested. His proclamation was delayed due to a case filed against him that claimed he was an American citizen. Manzano was born in San Francisco, California in 1955 to both Filipino parents.
The Commission on Elections (Comelec), however, sided with Manzano, saying that he did not take an oath of allegiance to the US, and that he was even a registered voter in the past elections.
Manzano stayed in his post for just one term. He ran for mayor in the 2001 elections but lost to Jejomar Binay – the same official who defeated him in the 2010 vice presidential elections.
Emilio Mario "Lito" Osmeña
Another contested local poll victory was that of Osmeña, who won as Cebu governor in the 1988 elections.
His proclamation was also suspended after a petition was filed, which claimed that he is an American citizen, and that he holds an Alien Certificate of Registration.
Osmeña was born on September 11, 1938 in Cebu to a Filipino father (Emilio Osmeña, son of former president Sergio Osmeña) and a foreigner mother.
The Comelec dismissed in June 1988 the disqualification case "for not having been timely filed and for lack of sufficient proof that [Osmeña] is not a Filipino citizen."
1998 and 2013 elections
The former Manila City mayor has been faced with questions about his citizenship not just in one instance.
In the 1998 elections, when he ran for president, a petition was filed to disqualify Lim due to his citizenship. Petitioners claimed that a 1929 birth certificate found in the National Archives mentioned that his parents are "Chinese Mestizo and Chinese Mestiza." A second birth certificate issued a year later indicated that his parents are Filipino.
The Comelec dismissed the petition, saying that a birth certificate simply can't prove one's citizenship.
The Supreme Court didn't proceed with deciding on the merits of the case, however, as Lim eventually lost in that presidential race.
The issue was again raised in the 2013 elections, when former president Joseph Estrada hinted at the possibility of filing a disqualification case against rival Lim. The filing didn't push through, however, and Estrada eventually won in the polls.
Reyes ran and won as Marinduque representative in 2013. But she still ended up being disqualified due to a case filed against her.
The case against her stemmed from a blog article that showed documents of Reyes using her US passport on June 30, 2012, and records from the Bureau of Immigration (BID) showing that she is an American citizen.
Reyes claimed she has always been a natural-born Filipino, and that she has renounced the American citizenship she acquired because of her marriage. She even denounced the blog article as "hearsay".
The Supreme Court initially ruled against Reyes, with Reyes claiming that Associate Justice Presbitero Velasco Jr influenced the decision. Velasco is the father of Reyes' opponent in the 2013 polls.