May a treaty violate international law? If your answer is in the affirmative, explain when such may happen. If your answer is in the negative, explain why. (5%)

No, a treaty may not violate international law. In relation to the five essential requisites of a valid treaty which are : a) entered by parties with treaty-making capacities b) through their authorized representatives c) without the attendance of duress, fraud, mistake or other vice of consent d) on any lawful subject-matter e) in accordance with their respective constitutional processes.

Specifically, in the Treaty of Tordesillas in 1494, ,rendered invalid when it sought to divide parts of the Ocean which are open seas under the law of nations. Similarly, a treaty with such unlawful purposes such traffic in white slavery or narcotics are contrary to international law and public morality would be null and void.

Therefore, any subject-matter or purposes of a treaty contrary to international law are deemed unlawful and renders it invalid.

- III -
The President alone without the concurrence of the Senate abrogated a treaty. Assume that the other country-party to the treaty is agreeable to the abrogation provided it complies with the Philippine Constitution. If a case involving the validity of the treaty abrogation is brought to the Supreme Court, how should it be resolved? (6%)

In the Philippine setting the power to ratify a treaty is vested in the President. The role of the Senate is confined simply to giving or withholding its consent (veto power). For this matter, it is competent for the President to refuse to submit a treaty to the Senate or having secure its consent for its ratification , to refuse to ratify it. But, as a rule he cannot ratify a treaty without the concurrence of 2/3 of all members of the Senate.

Under this rule, the general practice of treaty-making power is vested to the executive department of the government. The President holds the highest executive office. Thus, the President as provided for in the Constitution has the power to abrogate a treaty if such act obtained the consent of the other country-party. It is not therefore necessary for the Senate to give its concurrence as such is only needed upon ratifying a treaty.

The case involving the validity of the treaty abrogation without Senate’s concurrence is not tenable. The Senate’s consent is only necessary upon ratification. As provided, both country-parties already mutually agreed in the abrogation thus, the President alone can abrogate the treaty as a valid act of his executive power under his treaty-making capacity.