By ADAM LIPTAK

WASHINGTON - Judges around the world have long looked to the decisions of the United States Supreme Court for guidance, citing and often following them in hundreds of their own rulings since World War II.
But now American legal influence is waning. Even as a debate continues in the court over whether its decisions should ever cite foreign law, a diminishing number of foreign courts seem to pay attention to the writings of American justices.
“One of our great exports used to be constitutional law,” said Anne-Marie Slaughter, the dean of the Woodrow Wilson School of Public and International Affairs at Princeton University in New Jersey.
From 1990 through 2002, for instance, the Canadian Supreme Court cited decisions of the United States Supreme Court about a dozen times a year, an analysis by The New York Times found. In the six years since, the annual citation rate has fallen by half, to about six.
Australian state supreme courts cited American decisions 208 times in 1995, according to a study by Russell Smyth, an Australian economist. By 2005, the number had fallen to 72.
The story is similar around the globe, legal experts say, particularly in cases involving human rights. These days, foreign courts in developed democracies often cite the rulings of the European Court of Human Rights in cases concerning equality, liberty and prohibitions against cruel treatment, said Harold Hongju Koh, the dean of the Yale Law School. In those areas, Dean Koh said, “they tend not to look to the rulings of the U.S. Supreme Court.”
The rise of new and sophisticated constitutional courts elsewhere is one reason for the Supreme Court’s fading influence, legal experts said. The new courts are, moreover, generally more liberal than the Supreme Court of recent years and for that reason more inclined to cite one another.
Another reason is the diminished reputation of the United States in some parts of the world, which experts here and abroad said is in part a consequence of the Bush administration’s unpopularity .
The adamant opposition of some Supreme Court justices to the citation of foreign law in their own opinions also plays a role, some foreign judges say.
“Most justices of the United States Supreme Court do not cite foreign case law in their judgments,” Aharon Barak, then the chief justice of the Supreme Court of Israel, wrote in the Harvard Law Review in 2002. “They fail to make use of an important source of inspiration, one that enriches legal thinking, makes law more creative, and strengthens the democratic ties and foundations of different legal systems.”
The signature innovations of the American legal system - a written Constitution, a Bill of Rights protecting individual freedoms and an independent judiciary with the power to strike down legislation - have been consciously emulated in much of the world. And American constitutional law has been cited and discussed in countless decisions of courts in Australia, Canada, Germany, India, Israel, Japan, New Zealand, South Africa and elsewhere.
In a 1996 decision striking down a law that made it a crime to possess pornography, for instance, the Constitutional Court of South Africa conducted a broad survey of American First Amendment jurisprudence, citing some 40 decisions of the United States Supreme Court.
Sending American ideas about the rule of law abroad has long been a source of pride. “The United States Supreme Court is the oldest constitutional court in the world - the most respected, the most legitimate,” said Charles Fried, a law professor at Harvard who served as solicitor general in the Reagan administration.
But there is an intense and growing debate about whether that influence should be a one-way street.
Justice Sandra Day O’Connor, in a speech before her retirement from the Supreme Court, advocated taking as well as giving.
“I suspect that with time we will rely increasingly on international and foreign law in resolving what now appear to be domestic issues,” Justice O’Connor said. “Doing so may not only enrich our own country’s decisions; it will create that allimportant good impression. ”