G.R No. 187167 August 16, 2011PROF. MERLIN M. MAGALLONA, AKBAYAN PARTY-LIST REP. RISA HONTIVEROS,PROF. HARRY C. ROQUE, JR., AND UNIVERSITY OF THE PHILIPPINES COLLEGE OFLAW STUDENTS, ALITHEA BARBARA ACAS, VOLTAIRE ALFERES, CZARINA MAYALTEZ, FRANCIS ALVIN ASILO, SHERYL BALOT, RUBY AMOR BARRACA, JOSEJAVIER BAUTISTA, ROMINA BERNARDO, VALERIE PAGASA BUENAVENTURA, EDANMARRI CAÑETE, VANN ALLEN DELA CRUZ, RENE DELORINO, PAULYN MAY DUMAN,SHARON ESCOTO, RODRIGO FAJARDO III, GIRLIE FERRER, RAOULLE OSENFERRER, CARLA REGINA GREPO, ANNA MARIE CECILIA GO, IRISH KAY KALAW,MARY ANN JOY LEE, MARIA LUISA MANALAYSAY, MIGUEL RAFAEL MUSNGI,MICHAEL OCAMPO, JAKLYN HANNA PINEDA, WILLIAM RAGAMAT, MARICARRAMOS, ENRIK FORT REVILLAS, JAMES MARK TERRY RIDON, JOHANN FRANTZRIVERA IV, CHRISTIAN RIVERO, DIANNE MARIE ROA, NICHOLAS SANTIZO,MELISSA CHRISTINA SANTOS, CRISTINE MAE TABING, VANESSA ANNE TORNO,MARIA ESTER VANGUARDIA, and MARCELINO VELOSO III,Petitioners,vs.HON. EDUARDO ERMITA, IN HIS CAPACITY AS EXECUTIVE SECRETARY, HON.ALBERTO ROMULO, IN HIS CAPACITY AS SECRETARY OF THE DEPARTMENT OFFOREIGN AFFAIRS, HON. ROLANDO ANDAYA, IN HIS CAPACITY AS SECRETARY OFTHE DEPARTMENT OF BUDGET AND MANAGEMENT, HON. DIONY VENTURA, IN HISCAPACITY AS ADMINISTRATOR OF THE NATIONAL MAPPING & RESOURCEINFORMATION AUTHORITY, and HON. HILARIO DAVIDE, JR., IN HIS CAPACITY ASREPRESENTATIVE OF THE PERMANENT MISSION OF THE REPUBLIC OF THEPHILIPPINES TO THE UNITED NATIONS,Respondents.D E C I S I O NCARPIO, J.:The CaseThis original action for the writs of certiorari and prohibition assails the constitutionality of RepublicAct No. 95221ﾧ(RA 9522) adjusting the country’s archipelagic baselines and classifying the baselineregime of nearby territories.The AntecedentsIn 1961, Congress passed Republic Act No. 3046 (RA 3046)2ﾧdemarcating the maritime baselines ofthe Philippines as an archipelagic State.3ﾧThis law followed the framing of the Convention on theTerritorial Sea and the Contiguous Zone in 1958 (UNCLOS I),4ﾧcodifying, among others, thesovereign right of States parties over their "territorial sea," the breadth of which, however, was leftundetermined. Attempts to fill this void during the second round of negotiations in Geneva in 1960(UNCLOS II) proved futile. Thus, domestically, RA 3046 remained unchanged for nearly fivedecades, save for legislation passed in 1968 (Republic Act No. 5446 [RA 5446]) correctingtypographical errors and reserving the drawing of baselines around Sabah in North Borneo.In March 2009, Congress amended RA 3046 by enacting RA 9522, the statute now under scrutiny. Thechange was prompted by the need to make RA 3046 compliant with the terms of the United NationsConvention on the Law of the Sea (UNCLOS III),5ﾧwhich the Philippines ratified on 27 February1984.6ﾧAmong others, UNCLOS III prescribes the water-land ratio, length, and contour of baselinesof archipelagic States like the Philippines7ﾧand sets the deadline for the filing of application for theextended continental shelf.