After the Philippines gained its independence from the United States on 4 July 1946, it continued to live under the 1935 Constitution, with its definition of the national territory. It did so until the promulgation by President Ferdinand E. Marcos of a new Constitution in January 1973.

The 1973 Philippine Constitution

A Constitutional Convention, with over 300 members, had been drafting the new Constitution, since June 1971, when Marcos declared martial law in September 1972. The Convention continued working under martial law conditions. The final text was ratified in a nationwide plebiscite in January 1973. Like the 1935 Constitution, the 1973 document went out of its way to define the national territory. Article 1 of the 1973 Constitution had this to say about the subject:

As in 1934, the 1971–72 Constitutional Convention debated the need to define the national territory in the new Constitution. Led by E. Voltaire Garcia II, some of the delegates argued against the inclusion of such a definition. One of the grounds for the argument was that a definition would preclude the country from pursuing later territorial claims. Delegates also pointed out that questions of territory should be governed by international, rather than municipal, law. Related to this argument was the proposition that the actual exercise of authority over territory was a stronger basis for a claim than a unilateral declaration, which, in any case, was not binding on other nations. Moreover, basing territorial positions on treaties between colonial powers, as the original text of the proposed provision did, would only serve to remind Filipinos of their colonial past.

Other delegates asserted that a provision defining the national territory would serve notice to the world of the country's territorial jurisdiction and reaffirm its sovereignty over its internal waters and territorial sea.