The case of Vinuya v. Romulo (G.R. No. 162230, April 28, 2010; 633 Phil. 538 [En Banc, Per J. Del Castillo) is about the tragic comfort women system, a legacy of the Rape of Nanking. In December 1937, Japanese military forces captured the City of Nanking in China and began a "barbaric campaign of terror" known as the "Rape of Nanking," which included the rapes and murders of an estimated 20,000 to 80,000 Chinese women, including young girls, pregnant mothers, and elderly women. Later, this barbaric campaign reached the Philippines during the Japanese occupation.

Petitioners in this case wanted the Executive Department to espouse their claims for an official apology from the Japanese Government and other forms of reparations against Japan.

According to the Supreme Court, from a domestic law perspective, the Executive Department has the exclusive prerogative to determine whether to espouse petitioners’ claims against Japan. In fact, the Executive Department had determined that taking up petitioners’ cause would be inimical to our country’s foreign policy interests and could disrupt relations with Japan, thereby creating serious implications on the stability of the region. This determination, the Supreme Court said it could not overturn.

In the first page of Vinuya decision, the Supreme Court emphasized that there is a broad range of vitally important areas that must be regularly decided by the Executive Department without either challenge or interference by the Judiciary. One such area involves the delicate arena of foreign relations. It would be strange indeed if the courts and the executive spoke with different voices in the realm of foreign policy. Precisely because of the nature of the questions presented, and the lapse of more than 60 years since the conduct complained of, the Court said it could not make any attempt to lay down general guidelines covering other situations not involved in the case, and had to confine the opinion only to the very questions necessary to reach a decision on the matter.

Also, the Supreme Court said that, from an international law perspective, the Philippines is not under any international obligation to espouse petitioners’ claims. In the international sphere, traditionally, the only means available for individuals to bring a claim within the international legal system has been when the individual is able to persuade a government to bring a claim on the individual’s behalf. Even then, it is not the individual’s rights that are being asserted, but rather, the state’s own rights.

Even petitioners’ invocation of jus cogens norms and erga omnes obligations did not alter the Supreme Court’s analysis. Petitioners failed to show that the crimes committed by the Japanese army violated jus cogens prohibitions at the time the Treaty of Peace was signed or that the duty to prosecute perpetrators of international crimes is an erga omnes obligation or has attained the status of jus cogens.

The foregoing discussions regarding the case of Vinuya v. Romulo show that public international law principles are not as grounded or as stable as domestic laws. While private international law principles also evolve, they are nevertheless based on some domestic law understanding of or anchored on codified rules on private transactions such as contracts and not on some esoteric principles that states happen to agree on over time.

While public international law rules heavily rely on the consent of states for compliance therewith, private international law rules are enforceable by local forums through their coercive powers. All things being equal, the consent of parties in a conflicts case is generally of no moment in its resolution.