Nearly a decade after five of Osama bin Laden's followers infiltrated the U.S. and carried out the terrorist attacks of 9/11, top lawmakers and Homeland Security officials today hailed improvements in border security but warned of the threat still posed by those who enter the country legally and overstay their visas.
"One of the great achievements since 9/11 is the extent to which we have secured our borders against those who would come in to do us harm," said Senate Homeland Security Chairman Joe Lieberman, I-Conn., at a committee meeting in Washington.
"Despite a lot of congressional effort and DHS effort, we still lack an exit system that will effectively identify people who've overstayed their visas in real time," he said. "This both undercuts the legitimacy of the law we have ... but it also threatens our security."
The Pew Hispanic Center estimates that between 4 million and 5.5 million -- nearly half -- of all undocumented immigrants living in the U.S. entered the country legally and then remained beyond the expiration of their visas.
A new Government Accountability Office report released today concluded that 36 percent of the roughly 400 individuals convicted of terrorism-related crimes in the U.S. since 2001 were "overstays."
"Despite the killing of Osama bin Laden, we must never forget that the battle against Islamic extremism is still very much on," said Sen. Susan Collins, R-Maine, the ranking member of the Senate Homeland Security Committee.
The GAO found that Immigration and Customs Enforcement -- the agency responsible for enforcing visa overstays -- has allotted only 3 percent of its work force to investigating individuals who have not left the U.S. when their visas expired.
The agency has arrested approximately 8,100 people who have overstayed, according to the report. But a GAO examination of a computerized U.S. immigration system that tracks U.S. visitors found a backlog of 1.6 million potential overstays that had not yet been reviewed.
The Department of Homeland Security is considering ways to beef up its tracking of the arrival and departure of immigrants and share the information with other agencies, officials said.
Homeland Security Secretary Janet Napolitano, though, said that stepping up investigations of those who overstayed visas or entered the country illegally was costly and labor intensive, especially if they had not committed a crime to make themselves more easily identifiable.
Napolitano said she has asked Congress for additional funds to sustain enforcement programs and hire more officers, but because of federal budget constraints, some of the requests have been turned down.
"We have to have some way to parse the population that is already in the country illegally given that we are only given the resources to remove about 400,000 people per year," she said. "We want to focus on those who are security threats, who are criminals and who are fugitives."
Still, Napolitano has said that by many measures the borders are as secure, and scrutiny of arriving foreign visitors is higher than ever before.
Apprehensions of illegal migrants crossing the nation's borders, a key indicator of illegal immigration, have plummeted, down 47 percent in the past four years, according to the Department of Homeland Security.
The number of illegal immigrants arrested and deported from the U.S. has reached record highs, with a growing emphasis on capturing those engaged in criminal activities, the agency says. The U.S. removed more than 392,000 immigrants last year and is on pace to eclipse that number in 2011.
The number of Border Patrol agents has more than doubled since 2004, unmanned aerial drones patrol the U.S.-Mexico border from California to Texas and construction has been completed on all but three miles of the southern border fence approved by Congress.
"The steps that have been taken constitute the most comprehensive and dedicated effort to border security that our country has ever deployed," Napolitano told the Senate panel today.