THE HAGUE - The execution of a Mexican citizen by the United States against the orders of the UN's highest court highlights a flaw in international law that enables countries to snub rulings without repercussions, experts say.
While the International Court of Justice's (ICJ) orders are binding, their execution are left up to states who consent voluntarily to the court's jurisdiction, they told AFP.
And while such a system theoretically enables states to act with impunity, it could never be altered for the risk of encroaching upon state sovereignty.
"International law cannot bind a state against its will, simply because we don't have a world government, a world legislature, or a world judicial system," said Jann Kleffner, international law professor at the University of Amsterdam.
"The will of the international community cannot be imposed on states just like that."
The US state of Texas on Tuesday put to death a Mexican convicted of murder in defiance of an order of the ICJ and ignoring a last-minute appeal from UN Secretary General Ban Ki-moon.
Jose Ernesto Medellin, 33, was killed by lethal injection for the 1993 rape and murder of two girls, aged 14 and 16, in Houston.
In 2004, the ICJ ruled that Medellin's conviction and those of other Mexicans facing execution in the United States violated the Vienna Convention because authorities failed to inform the foreigners of their right to consular access and assistance during trial.
US President George Bush subsequently ordered that the cases be reviewed, but the US Supreme Court ruled in March that the constitution did not allow for this to happen.
Last month, the ICJ ordered the United States to do all it can to stay the imminent execution of five Mexicans on death row, including Medellin, pending its final ruling in another Mexican bid to have the men's cases reviewed.
Annemarieke Vermeer, international law lecturer at the University of Leiden, said the ICJ would continue finding itself in difficult terrain in matters so close to the essence of state sovereignty as domestic justice.
"The court cannot order a state to change its systems," she said.
Analysts agreed that Medellin's execution was a blow to the ICJ as it brought its relevance into question.
And it may lead other states to emulate the United States when it suited them.
But while the tribunal has no enforcement powers of its own, states that ignore its judgments risk their international reputation and endanger reciprocal agreements with other states.
In another famous snub of the ICJ, Israel ignored a 2004 ruling that parts of a barrier it had built on Palestinian land were illegal and should be torn down.
"If for no other reason, governments need to respect the judgments of the ICJ out of long-term self-interest," said David Fathi, director of the US programme of lobby group Human Rights Watch.
"Even if a state does not like a ruling of the ICJ, it is in everybody's long-term interest that we have an international system governed by the rule of law."
The ICJ was by no means a worthless institution, argued Kleffner, as illustrated by the fact that most of its rulings were complied with -- even unpopular ones.
And while it was too late for Medellin, the ruling in this case will undoubtedly force the United States to adhere to the Geneva Convention more closely in similar trials in future.
"Most countries are sensitive to negative international judgments, they don't want to be shamed," said Vermeer.
And the ICJ will remain a viable means of settling disputes "because it is apolitical and a relatively cheap alternative to international arbitration."
Since the 2004 ruling, some US states have agreed to review their death row cases.
Texas has refused, arguing that its state courts were not bound by the ICJ treaty, a contention rubbished by experts.
The US Congress, meanwhile, has indicated it may pass legislation allowing states to comply with ICJ orders.
"I don't think this would ever have happened without the ICJ judgment," said Vermeer.
© 2008 Agence France Presse