WASHINGTON, United States (AFP) – How much sovereignty does the island of Puerto Rico possess? The US Supreme Court on Wednesday took up that question, a crucial one for a Caribbean territory torn between its ties to the United States and its desire for greater autonomy.

The debate on that fundamental issue lately has been overshadowed by a debt crisis that has engulfed the US possession, underscoring its complicated relationship with the mainland.

On Monday, it defaulted on payments on its $70 billion debt and its leaders have pressed the US Congress to grant it court-supervised bankruptcy protection to restructure its debt, a separate issue that the Supreme Court has agreed to hear later this year.

With the economic crisis as a backdrop, the court’s nine justices on Wednesday examined Puerto Rico’s hybrid status as a self-governing commonwealth whose four million inhabitants are US citizens.

As is often the case with the Supreme Court, the justices were weighing a narrow legal issue that could have much broader consequences.

The case before them involves two inhabitants of Puerto Rico, Luis Sanchez Valle and James Gomez Vasquez, who were charged locally with an illegal weapons sale.

The defendants opted to plead guilty to similar charges before a federal court, which sentenced them to prison.

Their lawyers then asked Puerto Rico to drop its charges against the pair, arguing that the US Supreme Court forbids a person being judged twice for the same crime.

Puerto Rico’s Supreme Court ruled in favor of the men, affirming that the former Spanish colony is an American territory and as such not a sovereign state.

Puerto Rico’s government, however, petitioned the US Supreme Court, insisting to the contrary that its sovereignty is based on a constitution adopted by referendum in 1952.

It further contends that Puerto Rican laws derive from its constitution and are passed by a popularly elected legislature, and that the US Congress blessed that autonomy.