Meanwhile, Associate Justices Antonio Eduardo Nachura and Diosdado Peralta inhibited themselves.

Puno, who called the VFA a continuing “slur on our sovereignty”, argued that the VFA has not been ratified as a treaty by the United States and that its provisions are not fully enforceable under US law.

Art. XVIII, Sec. 25 of the Constitution provides that:

After the expiration in 1991 of the Agreement between the Republic of the Philippines and the United States of America concerning military bases, foreign military bases, troops, or facilities shall not be allowed in the Philippines except under a treaty duly concurred in by the Senate and, when the Congress so requires, ratified by a majority of the votes cast by the people in a national referendum held for that purpose, and recognized as a treaty by the other contracting State.

Passed by the Philippine Senate and signed by then-President Joseph Estrada in 1999, the VFA among other things grants extra-territorial and extra-judicial “rights” to US servicemen visiting the Philippines for “military exercises”. It was not, however, recognized by the US government as a treaty.

Carpio, meanwhile, cited in his own dissenting opinion the US Supreme Court ruling on Medellin v. Texas.

The case of Medellin v. Texas refers to the question of whether decisions of the International Court of Justice (ICJ) may be enforced in the US as binding domestic law.

In 2003, the Mexican government filed a case against the US government before the ICJ concerning 51 Mexican nationals who had all been accused of committing crimes before US courts. One of them was Jose Ernesto Medellin, who had been convicted of rape and murder in Houston, Texas in 1997. In the case, called the Case Concerning Avena and Other Mexican Nationals (Mex. v. U. S.), Mexico alleged that the US had failed to inform the 51 Mexican nationals of their right to contact their consulate under the Vienna Convention on Consular Relations of April 24, 1963 – to which the US was a signatory.

Medellin’s 1997 conviction was then already under appeal for several years.

In 2004, the ICJ ruled in Avena that the 51 Mexican nationals were entitled to a review and reconsideration of their convictions and sentences.