ACCORDING TO the libel laws of some nations, even the truth is no defense. In 1959, Liberace sued London’s Daily Mirror for libel after one of its columnists referred to him as “fruit-flavoured” — and won. (“I cried,” he said, “all the way to the bank.”) In many countries, libel suits can chill speech or bankrupt independent authors and small publications — including American writers and publishers who fall victim to “libel tourism.”

When Rachel Ehrenfeld published a book alleging that Saudi billionaire Khalid bin Mahfouz had funded terrorist activity, he sued her under British libel law, even though only 23 copies of her book had been sold there — and won a judgment for more than $200,000. After New York Times writer Joe Sharkey’s airplane crashed in Brazil, he returned and wrote a piece exposing the air traffic control failures that had resulted in the accident. Now he is being sued for libel by a woman who claims he injured her by insulting the honor of Brazil.

To end the threat of such foreign cases, Congress unanimously passed the Securing the Protection of our Enduring and Established Constitutional Heritage Act, or Speech Act. On Tuesday, President Obama signed the bill into law, preventing courts from enforcing foreign judgments in libel cases that would not pass muster by U.S. standards. Even when the plaintiff does not seek to enforce a foreign court’s ruling, the law makes it possible for the defendant to ask for a ruling that labels the libel judgment “repugnant to the Constitution or laws of the United States,” offering protection to reputations as well as finances.

The fact that such a law was required at all is a poor reflection on the status of libel law abroad — especially in the United Kingdom. Libel tourists flock to London, where suits can result in judgments of millions of pounds, effectively placing some wealthy figures outside the reach of journalism because writing about them might prove too costly. Britain needs to reform a system under which noncitizens can sue publications with only tangential connections to the United Kingdom. Fortunately, all three major parties have declared libel reform a priority, and the British Ministry of Justice has announced it will move forward with legislation in the coming year. The Speech Act should serve as a goad to action.