It is a rare achievement these days for the Senate to pass anything of real substance by a unanimous vote. But an important bill that protects Americans from the whims of foreign libel judgments was passed earlier this week by unanimous consent. Once it passes the House and is signed into law, it will provide a safeguard to authors and publishers threatened with ruinous foreign judgments.

In the United States, a plaintiff alleging libel must prove that a statement is false and defamatory, and public figures have to show that a writer acted with actual malice in making a false statement. But these protections, rooted in the First Amendment, do not exist in places like Britain, Australia and Singapore, where the burden is often on the author, once accused of libel, to show that a statement is true.

To sidestep American protections, subjects of books have sued publishers and authors in British courts where they have a better chance of winning. The practice, known as libel tourism, counts on a system in which American courts will enforce British fines and penalties.

The bill passed by the Senate on Monday would prohibit American courts from enforcing foreign defamation judgments if the judgments are inconsistent with First Amendment protections. In other words, if a British court finds that an American author has committed libel but has not conducted the trial with the same legal standards as an American court, the judgment against the author would be void in the United States. Americans who are found overseas to have committed libel can also sue in federal court to have that judgment found to be “repugnant to the Constitution” or American law.