MANILA, Philippines -- The baselines bill approved by the House of Representatives, which seeks to set the national territory, is ?fatally flawed? and a ?potential diplomatic disaster,? Senator Miriam Defensor-Santiago said Tuesday.

Santiago, who chairs the Senate committee on foreign affairs, said it is ?futile? to include disputed islands in the South China Sea within the country?s archipelagic baseline because many of these are already occupied by several Southeast Asian countries and China that also lay claim to the territory.

?It defies reality when a state claims sovereignty over islands, which are in the physical possession of other states,? she said in a statement on Tuesday.

House Bill 3216, or An Act Defining the Archipelagic Baselines of the Philippine Archipelago, was approved on third reading Tuesday by a vote of 177 in favor and three against, with no abstentions.

The House version of the proposed measure includes in the national territory Scarborough Shoal and Kalayaan group of islands, part of the Spratlys chain, which is being claimed wholly or in part by the Philippines, China, Vietnam, Malaysia and Brunei.

In contrast, the approved Senate version of the bill classifies the disputed territory as a ?regime of islands.?

Santiago said Senate President Juan Ponce Enrile should head the chamber?s delegation to the bicameral committee, which will reconcile both versions of the bill, since the House panel will be led by Speaker Prospero Nograles.

She said she had the ?fullest confidence in the analytical judgments? of both Nograles and Enrile.

The country has to come up with a baselines law that will define the national territory by May 13 this year, the deadline set by the United Nations Convention on the Law of the Sea.

?It is really a very simple choice,? Santiago said. ?We have to scale down without surrendering our territorial claims. The unacceptable choice is to claim as much territory as we want, alienate the rest of the international community, and operate as a pariah [under] international law.?

Enrile agreed that the Senate version of the bill was the ?more realistic approach to the problem.?

?We all agreed that we consider Kalayaan as ours. All Filipinos agree on that. But it is a question of legal engineering. How do you approach the problem in relation to the claims of other countries?? he asked.

Designating Scarborough and the Kalayaan group as a regime of islands would ensure that the country?s claim to the territory remains, Enrile said.

?But there are also other claimants, and we have to deal with that problem, both from the viewpoint of the [country?s] internal law, which is disputed by other countries, and from the viewpoint of the international law, [under] which they will recognize our claim based on a regime of islands,? he said.

Enrile also noted that the country lacked the military capability to enforce its claim.