(James Pan/Courtesy of State Department)

Chris Smith, a Republican from New Jersey, is a member of the U.S. House of Representatives.

As principal author of the Trafficking Victims Protection Act of 2000 — a landmark law combatting sex- and labor-trafficking at home and abroad — I am deeply concerned that the United States has not done enough to address the rape and sexual abuse of children by convicted pedophiles who travel in secret to countries where child sex tourism thrives.

That concern is shared by many, and it’s why a unanimous Congress recently passed legislation, which I sponsored as it was refined over eight years, to significantly expand protections for children worldwide. Now awaiting the president’s signature, H.R. 515 — the International Megan’s Law — authorizes the creation of a comprehensive, reciprocal notification system between U.S. and foreign law enforcement regarding the travels of those required by law to be on government sex-offender registries.

This is a serious problem. State Department Trafficking in Persons Reports identify several dozen countries that are destinations for child sex tourism, including Mexico, the Philippines, Brazil and Thailand. Just last month the United Nations noted with alarm increasing child sex tourism in Peru. These governments need to know when convicted pedophiles cross their borders.

A 2010 Government Accountability Office report found that at least 4,500 U.S. passports were issued to registered sex offenders in fiscal 2008 alone. Typically, a passport is valid for 10 years, meaning that currently tens of thousands of offenders could be traveling abroad as child sex tourists. Studies demonstrate that even when caught, some child predators have a propensity to reoffend. For example, a 2009 study by Mark E. Olver, Stephen C.P. Wong and Terry P. Nicholaichuk, one of many available on the Justice Department’s SMART Web site, found that untreated moderate- to high-risk sex offenders were reconvicted for sex crimes at a rate of 17.7 percent after three years and 32 percent after 10 years.

The most remarked-upon provision of the law is a mandate that an “identifier” — defined as a “visual designation affixed to a conspicuous location” — be placed on passports to indicate that holders appear on a U.S. sex-offender registry for an offense against children. Concerns have been raised about impeding the rights of citizens to travel. U.S. law denies passports to delinquent taxpayers, deadbeat parents and drug smugglers; the law’s passport provision, however, does not go this far. It simply would add an identifier deemed appropriate by the executive branch. And when the legal duty for the sex offender to register ends, so does the requirement for the passport identifier.

The International Megan’s Law honors the memory of Megan Kanka — a precious girl from my hometown of Hamilton, N.J., who was kidnapped, raped and brutally murdered in 1994 by a neighbor who, unbeknown to neighborhood residents, was a convicted sex offender.

As a result of hard work by Megan’s parents, Maureen and Richard Kanka, and others, all 50 states passed Megan’s laws requiring public notification of convicted sex offenders living in a community.

These registries have survived legal challenges across the country because of the compelling interest to protect children. Notably, the same arguments that failed to shut down sex-offender registries are now being employed against the International Megan’s Law. They were poor arguments then, and they are poor arguments now.