B. Archipelagic Doctrine and Baselines (U.N. Convention on the Law of the Sea [UNCLOS], Arts. 46–50; RA 9522)

Archipelagic Doctrine

A body of water studded with islands, or the islands surrounded with water, is viewed as a unity of islands and waters together forming one integrated unit. [N.B. Embodied in Art. I, specifically by the mention of the “Philippine archipelago” and the specification on “internal waters.”]

Treaty limits of the Philippine archipelago

• Treaty of Paris of 10 December 1898:

“Spain cedes to the United States the archipelago known as the Philippines Islands, and comprehending the islands lying within the following line” xxx

Article 3 defines the metes and bounds of the archipelago by longitude and latitude, degrees and seconds.

• Treaty of Washington of 7 November 1900 between the United States and Spain: Ceding Cagayan, Sibuto and Sulu.
• Treaty of 12 January 1930 between the United States and Great Britain: Ceding the Turtle and Mangsee Islands [Bernas (2003), cited in Justice Velasco’s concurring opinion in Magallona v. Ermita, G.R. No. 187167 (2011)].

Methods of Baseline Determination

Baselines laws such as R.A. No. 9522 are enacted by United Nations Convention on the Law of the Seas III (UNCLOS III) State parties to mark-out specific basepoints along their coasts from which baselines are drawn, either straight or contoured, to serve as geographic starting points to measure the breadth of the maritime zones and continental shelf. UNCLOS III and its ancillary baselines laws play no role in the acquisition, enlargement or, as petitioners claim, diminution of territory.

UNCLOS III has nothing to do with the acquisition (or loss) of territory. It is a multilateral treaty regulating, among others, sea-use rights over maritime zones (i.e., the territorial waters [12 nautical miles from the baselines], contiguous zone [24 nautical miles from the baselines], exclusive economic zone [200 nautical miles from the baselines]), and continental shelves that UNCLOS III delimits.

UNCLOS III was the culmination of decades long negotiations among United Nations members to codify norms regulating the conduct of States in the world's oceans and submarine areas, recognizing coastal and archipelagic States' graduated authority over a limited span of waters and submarine lands along their coasts. XXX Under traditional international law typology, States acquire (or conversely, lose) territory through occupation, accretion, cession and prescription, not by executing multilateral treaties on the regulations of sea-use rights or enacting statutes to comply with the treaty's terms to delimit maritime zones and continental shelves. Territorial claims to land features are outside UNCLOS III and are instead governed by the rules on general international law [Magallona v. Ermita, G.R. No. 187167 (2011)].

R.A. No. 9522 (March 10, 2009) - The current baselines law created 101 base points around the Philippines to determine the baseline. This aims to demarcate the country's maritime zone and continental shelf in accordance with UNCLOS III and is not meant to delineate Philippine territory. Under the Treaty of Paris, baselines cannot be drawn from the boundaries or other portions of the rectangular area but the outermost islands and drying reefs of the archipelago.

R.A. No. 9522 is not unconstitutional: (1) it is a statutory tool to demarcate the maritime zone and continental shelf of the Philippines under UNCLOS III and does not alter the national territory. (2) While UNCLOS III does not bind the Philippines to pass a baselines law, Congress may do so. (3) The law also does not abandon the country's claim to Sabah, as it does not expressly repeal the entirety of R.A. No. 5446.

R.A. No. 9522 uses the framework of regime of islands in determining the maritime zones of the Kalayaan Island Group (KIG) and Scarborough Shoal. An island is a naturally formed area of land, surrounded by water, which is above water at high tide; it generates maritime zones under UNCLOS Article 121, except that rocks which cannot sustain human habitation or economic life of their own have no exclusive economic zone or continental shelf [UNCLOS III].

Archipelagic baseline method — Draw straight archipelagic baselines joining the outermost points of the outermost islands and drying reefs, subject to UNCLOS Article 47. The enclosed waters are archipelagic waters under UNCLOS Article 49, without prejudice to the designation of internal waters under Article 50 (R.A. No. 9522; Magallona v. Ermita, G.R. No. 187167 (2011)).

R.A. No. 9522 amends R.A. No. 3046 (as amended by R.A. No. 5446). R.A. No. 3046 determined appropriate points of the outermost islands of the archipelago, then connected them by means of a straight line until all islands were surrounded or enclosed by the imaginary lines. R.A. No. 5446 states that the definition of the baselines of the territorial sea of the Philippine Archipelago is without prejudice to the delineation of the baselines of the territorial sea around the territory of Sabah, situated in North Borneo, over which the Republic of the Philippines has acquired dominion and sovereignty.

Normal Baseline Method

The baseline is drawn following the low-water line along the coasts as marked on large-scale charts officially recognized by the coastal State. This line follows the sinuosities of the coast and therefore would normally not consist of straight lines (UNCLOS, Art. 5; Bernas, 1987 Philippine Constitution: A Commentary, 23, 2009).

Straight Baseline Method

Consists of drawing straight lines connecting appropriate points on the coast without departing to any appreciable extent from the general direction of the coast, in order to delineate the internal waters from the territorial sea along qualifying coasts under UNCLOS Article 7. These differ from archipelagic baselines under UNCLOS Article 47, which generally enclose archipelagic waters under Article 49.

The Baseline Law (R.A. 9522, 2009)

R.A. No. 9522–amended R.A. No. 3046, entitled "An Act to Define the Baselines of the Territorial Sea of the Philippines;" specified that baselines of Kalayaan Group of Islands and Bajo de Masinloc (Scarborough Shoal) shall be determined as “Regime of Islands” under the Republic of the Philippines, consistent with the UNCLOS.

R.A. No. 9522 is constitutional:

• Under UNCLOS III, a baselines law identifies the limits used to measure the Philippines’ maritime zones and continental shelf. It does not change national territory. Territory may be acquired or lost through cession, accretion, prescription, or occupation (Magallona v. Ermita, G.R. No. 187167, 2011).
• RA 9522 does not abandon the Philippine claim to Sabah because it does not expressly repeal RA 5446 in its entirety (Magallona v. Ermita, G.R. No. 187167, Aug. 16, 2011).

RA 9522 also does not, by itself, turn internal waters into archipelagic waters subject to innocent passage. The Philippines retains sovereignty over waters landward of its baselines, the airspace above them, and the submarine areas beneath them. Acting within their constitutional powers, the political branches may designate routes through archipelagic waters to regulate innocent passage and sea lanes passage (Magallona v. Ermita, G.R. No. 187167, Aug. 16, 2011).

The definition of the baselines of the territorial sea of the Philippine Archipelago is without prejudice to the delineation of baselines around Sabah in North Borneo, over which the Philippines claims dominion and sovereignty (RA 5446).