Introduction

The 1987 Constitution of the Republic of the Philippines establishes the foundational principles governing citizenship, reflecting the nation's adherence to the principle of jus sanguinis (right of blood) rather than jus soli (right of soil). Article IV of the Constitution delineates who are considered citizens, the distinctions between natural-born and naturalized citizens, and the mechanisms for the loss and reacquisition of citizenship. These provisions are supplemented by statutory laws such as Commonwealth Act No. 63 (An Act Providing for the Ways in Which Philippine Citizenship May Be Lost or Reacquired), Commonwealth Act No. 473 (The Revised Naturalization Law), Republic Act No. 9139 (The Administrative Naturalization Law of 2000), and Republic Act No. 9225 (Citizenship Retention and Re-acquisition Act of 2003). This article comprehensively examines the acquisition and loss of Philippine citizenship, emphasizing constitutional mandates and their interplay with relevant legislation and jurisprudence.

Citizenship in the Philippine context is not merely a legal status but a bundle of rights and obligations, including the right to vote, hold public office (with restrictions for certain positions reserved for natural-born citizens), own land, and practice certain professions. The Constitution prioritizes the preservation of citizenship while addressing issues like dual allegiance, which is deemed inimical to national interest under Section 5 of Article IV.

Acquisition of Philippine Citizenship

Philippine citizenship can be acquired either by birth or through naturalization. The Constitution explicitly lists the categories of citizens in Section 1 of Article IV:

Those who were citizens of the Philippines at the time of the adoption of the 1987 Constitution (February 2, 1987).
Those whose fathers or mothers are citizens of the Philippines.
Those born before January 17, 1973 (the effectivity date of the 1973 Constitution), of Filipino mothers, who elect Philippine citizenship upon reaching the age of majority.
Those who are naturalized in accordance with law.

Acquisition by Birth

The Philippines follows jus sanguinis, meaning citizenship is transmitted through parental bloodline. Thus:

A child born to at least one Filipino parent, regardless of the place of birth, is a Filipino citizen from birth.
If both parents are Filipino, the child is unequivocally a citizen.
If only one parent is Filipino, the child acquires citizenship through that parent, provided the Filipino parent was a citizen at the time of the child's birth.

A special provision applies to children born before January 17, 1973, to Filipino mothers and alien fathers. Under the 1935 Constitution, such children followed the father's citizenship, but the 1973 and 1987 Constitutions retroactively allowed them to elect Philippine citizenship upon reaching 21 years of age (age of majority under the Civil Code at the time). This election must be express, typically through an affidavit filed with the civil registrar or a Philippine consulate. Failure to elect results in the loss of the opportunity to claim citizenship under this provision. Notably, those who elect are deemed natural-born citizens per Section 2 of Article IV.

Children born to Filipino parents abroad are citizens, but they must register the birth with the Philippine embassy or consulate to establish proof. Unregistered births may require judicial confirmation of citizenship later.

Natural-Born vs. Naturalized Citizens

Section 2 defines natural-born citizens as those who are citizens from birth without performing any act to acquire or perfect their citizenship. This includes:

Children born to Filipino parents.
Those electing under the pre-1973 provision, who are retroactively considered natural-born.

Natural-born status is crucial because certain constitutional privileges are reserved for them, such as:

Running for President, Vice-President, Senator, or Representative (Article VI, Sections 2-3; Article VII, Section 2).
Appointment to the Supreme Court or as Ombudsman (Article VIII, Section 7; Article XI, Section 8).
Ownership of private lands (limited for naturalized citizens under certain conditions).
Ownership of public utilities (Article XII, Section 11).

Naturalized citizens, in contrast, acquire citizenship through a deliberate process and may face restrictions.

Acquisition by Naturalization

Naturalization is governed by law, primarily Commonwealth Act No. 473 and Republic Act No. 9139. There are three main modes:

Judicial Naturalization (CA 473): Involves filing a petition with the Regional Trial Court after a declaration of intention (filed one year prior, waived for certain applicants like those born in the Philippines). Requirements include:
- At least 30 years of age (21 if born in the Philippines or married to a Filipino).
- 10 years of continuous residence (5 years if married to a Filipino or with special qualifications like speaking Philippine languages).
- Good moral character, belief in the Constitution, and no disqualifying convictions (e.g., crimes involving moral turpitude).
- Ability to speak and write English or Spanish and a principal Philippine dialect.
- Enrollment of minor children in Philippine schools.
- Ownership of real estate worth at least P5,000 or a lucrative trade/profession.
- Mingling socially with Filipinos and embracing Philippine customs.
The process includes a hearing, a two-year probationary period (certificate of naturalization issued after), and potential revocation for fraud.
Administrative Naturalization (RA 9139): For aliens born and residing in the Philippines since birth. Requirements are similar but streamlined:
- Born in the Philippines and resided continuously since birth.
- At least 18 years old.
- Good moral character, no criminal record.
- Education in Philippine schools with civic education.
- Proficiency in a Philippine language.
- Lucrative occupation or property.
Handled by a Special Committee on Naturalization, with a fee and appeal to the Secretary of Justice.
Legislative Naturalization: Rare, through a specific act of Congress granting citizenship to individuals with exceptional merits (e.g., foreign athletes or philanthropists).

Derivate citizenship extends to minor children of naturalized parents, but spouses must naturalize separately.

Other Modes of Acquisition

Repatriation: For natural-born Filipinos who lost citizenship (discussed below). Under RA 8171 (for those who lost due to political/economic necessity) or general laws.
Foundlings: Per jurisprudence (e.g., Poe v. COMELEC, 2016), foundlings found in the Philippines are presumed natural-born citizens unless proven otherwise, aligning with international conventions like the UN Convention on the Rights of the Child.

Loss of Philippine Citizenship

Section 3 of Article IV states that citizenship may be lost or reacquired as provided by law. The primary statute is Commonwealth Act No. 63, as amended by RA 106 (extending to women) and RA 9225.

Modes of Loss

Citizenship is lost voluntarily or involuntarily through:

Naturalization in a Foreign Country: Automatic loss upon acquiring foreign citizenship, unless under RA 9225 (see reacquisition).
Express Renunciation: By declaring in writing before a competent authority (e.g., Philippine consul) the renunciation of allegiance, often during foreign naturalization.
Subscribing to an Oath of Allegiance: To a foreign constitution or laws upon attaining majority, if holding dual citizenship by birth.
Rendering Service to Foreign Armed Forces: Or accepting a commission therein, unless the Philippines is at war with that country or it is under a mutual defense treaty (e.g., US-Philippines Mutual Defense Treaty allows service in US forces without loss).
Cancellation of Naturalization Certificate: For fraud, illegal acquisition, or subsequent disqualifying acts (e.g., residing abroad permanently within one year of naturalization).
Declaration as a Deserter: Of the Armed Forces of the Philippines in time of war, by competent authority.
Conviction for Certain Crimes: Though not explicit in CA 63, jurisprudence links loss to acts implying renunciation.

Historically, marriage of a Filipina to a foreigner caused loss under the 1935 regime, but Section 4 of Article IV now provides that citizens marrying aliens retain citizenship unless they renounce it by act or omission (e.g., acquiring the spouse's citizenship). RA 9225 reinforces this.

Involuntary loss is rare, as citizenship is protected under due process (Article III, Section 1). Dual citizens may lose Philippine citizenship if they perform acts of allegiance solely to the foreign state.

Effects of Loss

Loss results in alien status: loss of political rights, restrictions on land ownership (must dispose within one year per CA 63), and professional practice. Minor children may lose derivatively if both parents lose citizenship.

Reacquisition of Philippine Citizenship

Section 3 allows reacquisition by law. Key mechanisms:

Repatriation under CA 63: By taking an oath of allegiance before a consul or local civil registrar, and registering with the Bureau of Immigration. Applies to:
- Natural-born Filipinos who lost citizenship by foreign naturalization or political reasons.
- Women who lost by marriage (pre-1987).
RA 9225 (Dual Citizenship Law): Allows natural-born Filipinos who naturalized abroad to retain or reacquire Philippine citizenship without renouncing foreign citizenship. Process:
- File a petition with a Philippine consulate or the Bureau of Immigration.
- Take an oath of allegiance.
- Derivatives: Unmarried minor children also reacquire.
Reacquired citizens enjoy full civil and political rights, except those reserved for natural-born (unless originally natural-born). They must renounce foreign allegiance if running for public office.
RA 8171: Specific to those who lost citizenship due to political or economic necessity (e.g., refugees), with simplified repatriation.

Jurisprudence, such as Bengzon v. HRET (2001), clarifies that reacquired citizens under RA 9225 are restored to natural-born status if originally so.

Dual Citizenship and Allegiance

Section 5 declares dual allegiance inimical and to be dealt with by law. RA 9225 permits dual citizenship but requires renunciation of foreign allegiance for appointive/elective public office (administered via oath). Dual citizens may face conflicts in passports, taxation, and military service, resolved per treaties (e.g., Hague Convention on Nationality).

Jurisprudence and Evolving Interpretations

Key cases:

Mecano v. CSC (1992): Citizenship retained despite foreign marriage.
Mercado v. Manzano (1999): Dual citizens by birth must renounce foreign citizenship for elective office.
Poe-Llamanzares v. COMELEC (2016): Foundlings are natural-born; election under Section 1(3) confers natural-born status.
David v. Senate Electoral Tribunal (2016): Reaffirms RA 9225 restores full rights.

Administrative bodies like the Bureau of Immigration and Department of Justice handle disputes, with judicial review available.

Conclusion

The 1987 Constitution safeguards Philippine citizenship through bloodline transmission while providing structured paths for naturalization, loss, and reacquisition. Balancing national sovereignty with global mobility, these provisions, bolstered by laws like RA 9225, accommodate diaspora Filipinos. However, challenges persist in enforcement, dual allegiance, and proof of citizenship, underscoring the need for clear documentation and adherence to legal processes. Citizenship remains a core element of Philippine identity, protected yet adaptable to contemporary realities.