Each year, under the terms of the Visa Waiver Program, more than 10 million citizens from 27 different countries -- mostly in Europe -- enter the U.S. for 90 days or less without being required to go through the screening process of first obtaining a visa. Although it offers great economic benefits for the U.S., critics argue that terrorists who carry passports from these countries can easily gain entry to the U.S. and that the security risks outweigh the benefits of the program. Here's a look at the pros and cons.

With Europe increasingly seen as a recruiting and staging ground for Islamic terrorists, concern is growing about the Visa Waiver Program (VWP), which allows citizens from 27 countries -- 18 of them in Europe -- to enter the U.S. on a passport alone, bypassing the more careful screening given by well trained consular officials who judge eligibility for a visa.

Thanks to VWP, Zacarias Moussaoui, a citizen of France who was indicted as a co-conspirator in the 9/11 plot, was able to enter the U.S. using just his passport in February 2001. Richard Reid, a British citizen convicted of trying to detonate a bomb hidden in his shoe while he was flying from Paris to Florida in December 2001 also was able to board a plane bound for the U.S. with just his passport.

Citing the Moussaoui and Reid cases, Jan Ting, a former assistant commissioner of the Immigration and Naturalization Service (INS), said in his testimony before the 9/11 Commission, "Do we need more proof than that of the continuing threat to U.S. national security of the Visa Waiver Program?"

Congress enacted the VWP in the 1980s. Its economic benefits range from tourism and international trade to significant cost savings for the State Department. However, in a post-9/11 world, demand is growing for the program to be restricted, temporarily suspended or even eliminated.

Robert Leiken, director of immigration and national security programs at the Nixon Center, a public policy think tank in Washington, D.C., points out that second-generation Muslim immigrants in Europe, like Moussaoui and Reid, can use the VWP to enter the U.S. and it is a threat that is not being properly addressed.

"A lot of the second generation in Europe are radicalized for a variety of reasons," says Leiken, citing their exposure to extremist clerics, poverty, and a general lack of assimilation into their host cultures. "Nothing short of interviewing Visa Waiver Program travelers abroad, before they even board a plane, could ensure the program isn't exploited," Leiken says.

+ The US-VISIT Program

In April 2004, the Department of Homeland Security's Office of the Inspector General issued a report citing a number of security problems associated with VWP. It recommended that visitors arriving under the program should be subject, just like other foreign visitors, to US-VISIT, a Department of Homeland Security initiative started in early 2004 that requires travelers to check in (and in the future, to check out) at ports of entry with a digital fingerprint and photograph.

The recommendation was implemented five months later, which was a good sign, says Robert Ashbaugh, assistant inspector general for the Department of Homeland Security (DHS) Office of Inspector General. "That eliminates one of the most significant security implications," Ashbaugh says.

But critics such as the Nixon Center's Leiken argue US-VISIT procedures don't go far enough. "The entry and exit system doesn't help a lot," Leiken maintains, because to trip the system, an individual must have been involved in a crime or terrorism-related event, and then be placed on a watch list. Because of a lack of information sharing, an individual may be on one country's watch list, but not another's. "What you need is closer cooperation between U.S. and European authorities to coordinate between who's being watched," Leiken says.

Coordinating watch lists is an ongoing process; no single, all-encompassing watch list that contains information on suspects yet exists even between U.S. agencies, much less between the U.S. and all European countries.

+ Passport Fraud: "Little Reason to Fear Being Caught"

While US-VISIT may have added more safety to VWP, Robert Ashbaugh says the most serious concern remains: Criminals and terrorists aiming to enter the U.S. have created a big demand for stolen passports from the 27 countries covered by VWP.

In his June 2004 testimony before the House Committee on International Relations, James Sullivan, director of the U.S. National Central Bureau of Interpol, the international police force based in France, estimated that there "are in excess of 10 million" stolen passports in circulation worldwide, and that the problem is "probably more European-based than anything else."

And getting information about these stolen passports to people guarding ports of entry is problematic, says Ashbaugh of DHS's Office of Inspector General. "The whole reporting process by which the information has been distributed -- that issue has not been solved," he says.

This concern was underlined in December 2004, when the DHS Office of Inspector General released another report on VWP, this one focusing on passport theft. It offered a grim assessment: "Aliens applying for admission to the United States using stolen passports have little reason to fear being caught."

According to the report, only seven of the 27 VWP countries contribute stolen passport data to the stolen travel document database maintained by Interpol. Apart from Interpol's database, border officers must rely on a diverse stream of information on stolen passports that filters down through the State Department. While some countries use two numbers to identify a passport -- one created when it is made and another when it is issued -- border guards may only check one against a database; Ashbaugh calls this "the inherent two number problem."

One particularly troublesome example from the December report on stolen passports from VWP countries illustrates the system's flaws:

On June 6, 2001, thieves stole 708 blank passports from a VWP country. The theft was not reported to the U.S. government until April 2004. On April 23, 2004, CBP (Customs and Border Patrol) posted stolen passport lookouts for the stolen blank passports. The potential significance of the stolen passports is that they were stolen in the city that was also the location of the Al Qaeda cell that played a significant role in providing financial and logistical support for the September 11th terrorists. Between December 2001 and March 2004, 21 of these stolen passports were used by aliens attempting to enter the United States. In all cases, the attempted entries occurred before the lookouts were posted. Twenty of the aliens successfully entered the United States using the stolen passports… We could not confirm, however, that any of the aliens actually left the country, nor can we confirm that any are still here.

As long as this and other flaws exist, passport fraud will continue to be a possible route into the U.S. for terrorists. "[Europe] remains a place of fairly easy transit from outside of Europe through Europe to the United States," explains Michael Scheuer, the former chief of the CIA's bin Laden unit. "It is a place where there are well-established organized crime organizations that can be used for false documents or false residence passports."

But initiatives now are underway to make tracking passport fraud a priority.

Interpol has a growing database on stolen travel documents. The database currently holds 5.6 million entries submitted by 66 of 182 member countries -- a marked increase from summer of 2004, when it held roughly half that number of entries. The increase comes as more countries agree to add their information to the database; the U.S. began contributing its information in May 2004.

Kelly Shannon, a spokesperson for the Bureau of Consular Affairs at the State Department, points out another improvement: As of fall 2004, travelers from VWP countries now are required to have machine-readable passports. This also will increase the likelihood a stolen passport will be flagged. Getting into the U.S. is "not a simple as someone having a passport from one of those countries," Shannon says.

Europe also is making inroads into tracking stolen passports. Brian Woo, chief of the Action Against Terrorism Unit at the Vienna-based Organization for Security and Cooperation in Europe, which promotes law enforcement and security in Europe and Central Asia, says that since its creation in 2002, his unit has been holding training seminars to help immigration officials better identify and report stolen travel documents.

However, the system is still far from perfect. Interpol's growing database is a big help, says Woo, but it is difficult to make sure necessary information in the database gets to border guards. "It is one thing to build a good database and another to solve the last mile problem -- getting frontline personnel quick and easy access," he says.

+ Should the Visa Waiver Program Be Cancelled?

Recent improvements to increase the security of VWP have not halted criticism. Sen. Dianne Feinstein (D-Calif.) has proposed a moratorium on the program until security holes can be further patched up. Feinstein points to the case of Ahmad Ajaj, an indicted co-conspirator in the 1993 World Trade Center bombing who used a false Swedish passport to enter the U.S. under the program, as an example of ways it can be manipulated by terrorists.

But stopping the program, even temporarily, could have grave consequences. A 2002 report by the Department of Commerce estimated that a discontinuation of VWP would cost the U.S. economy more than $28 billion in tourism exports from 2003 to 2007, while costing the tourism industry 475,000 jobs over five years.

Theresa Brown, director of immigration policy at the U.S. Chamber of Commerce, reports that in 2002 visitors entering under the VWP contributed $66 billion to the U.S. economy in all industries combined. "None of that," says Brown, "takes into account business eventually transacted due to business people traveling in and out of the U.S., attending meetings, conventions and trade shows."

Brown says canceling the program "would impact across every sector of the economy," not least because it could trigger reciprocity arrangements from other countries that might begin limiting admittance of business travelers from the U.S.

Rick Webster, director of government affairs at the Travel Industry Association of America (TIA) says preserving the VWP is his highest concern. He says the TIA supports making the program more secure, but not at unnecessary expense. "Nothing is going to be 100 percent foolproof," Webster says. "There's risk in engaging in trade and travel with the rest of the world."

In addition to burdening business and alienating millions of law-abiding visitors to the U.S., the impact on the U.S. State Department would be significant if VWP were canceled. A 2002 report issued by the U.S. General Accounting Office (GAO) in 2002 estimated that initial costs to process the additional workload would likely range between $739 million and $1.28 billion. Annual recurring costs were estimated between $522 million and $810 million, an amount that would assume a large part of their operating budget, which for 2002 was $8.3 billion.

The State Department's Kelly Shannon declined to comment on whether there is a contingency plan should the program be cancelled, but acknowledges that it "would severely constrain our resources."

One US-VISIT requirement, for biometric information to be embedded in VWP country passports, has been delayed until October 2005. Shannon says the State Department lobbied for the extension because member countries are generally unequipped to meet the requirement, and had the delay not been granted, it would have resulted in "a spike of 5 million applicants for visas in one year alone," or a 70 percent increase in the department's non-immigrant visa workload.

+ Other Ways to Get In

Some observers have pointed out that focusing primarily on VWP as the security threat is misguided, because those who really want to get into the country and do harm could simply bribe their way into obtaining a visa.

Bribery for visas "clearly happens," says Mark Krikorian, executive director of the Center for Immigration Studies in Washington. The U.S. Department of Justice Bureau of Justice Statistics confirms that more than 1,600 defendants were tried in U.S. district courts between 1998 and 2002 under the federal statute prohibiting fraud and misuse of visas.

Terrorists could also circumvent the visa system altogether. No visa is needed to travel to the U.S. from Canada or Mexico; entry could be made at the borders with only a fake U.S. Green Card, or birth certificate and a driver's license.

Still, the security implications of VWP will probably remain controversial for some time. "Western Europe has all kinds of Islamist extremists," says Krikorian. "The threat of their using the VWP to enter undetected into the U.S. is not trivial." All that can be done, Krikorian said, is to tighten up as many potential gaps as possible -- whether through the improved detection of stolen passports that has developed recently, or the improved passenger screening under US-VISIT. "Nothing is foolproof; someone might eventually break in," Krikorian said, "but at least 99 percent of the bad guys will stay out."

John Letzing is a student at the Graduate School of Journalism at the University of California, Berkeley. His articles have appeared in the San Francisco Chronicle, Minneapolis City Pages, and the Santa Barbara News-Press.