Some members of Congress are pressing the Bush administration to shore up the U.S. border with Mexico, warning it could become a transit point for terrorists.
Ever since the 2001 terrorist attacks, the Bush administration and members of Congress from both major political parties have focused on the southern border with Mexico as a potential weak link in keeping terrorists out of the United States.
Earlier this year, FBI Director Robert Mueller warned lawmakers that immigrants with ties to al-Qaida could easily enter the United States illegally from Mexico using false identities.
In recent months, some members of the president's majority Republican Party have stepped up pressure on the administration to do more to crack down on illegal immigration.
Arizona Republican John Kyl, a member of a Senate subcommittee that deals with immigration issues, expressed concern about the continuing influx of illegal immigrants coming across the southern border during a recent hearing.
"Many of these aliens, incidentally, are not from Mexico, but they come from countries all over the world, usually flying into Mexico and then sneaking across the border on foot," he said. "Many do not have authentic identity documents. Many do not carry documents at all. We do not even know who many of them are. We do not know whether they intend to simply find work or whether they plan to engage in acts of terror in the United States or are here to commit crimes in our society."
There are an estimated 11 million undocumented immigrants in the United States. But federal immigration officials insist they are making progress in stemming the influx.
Border Patrol Chief David Aguilar recently briefed a Senate subcommittee on immigration about his agency's efforts since last October.
"The Border Patrol as a whole has apprehended over 800,000 illegal aliens, interdicted 886,000 pounds of marijuana and 7,400 pounds of cocaine. Our objective is nothing less than a border under operational control," he said.
But with that success have come other problems. State and federal officials complain they are running out of room to detain illegal immigrants suspected of criminal intentions or from so-called countries of special interest, which are known to have links with terrorist organizations.
Immigration officials have instituted a limited expedited removal program that detains the most suspicious illegal aliens and usually results in them being deported in about a month's time.
Large numbers of other illegal aliens who are not deemed a threat are often released inside the United States and told to appear in court at a later date to determine whether they are eligible to remain. A large number of them never make their court appearances.
Texas Republican Senator John Cornyn is joining forces with Senator Kyl to sponsor a bill that would double the size of the Border Patrol over the next five years.
"We cannot continue to ignore our border security or at least fail to provide the resources necessary to let our hard working men and women who are given that assignment and who have graciously accepted it, to be successful," he said.
If approved, the Cornyn-Kyl bill would authorize 10,000 new Border Patrol agents to the current total of 11,000. It would also offer a version of a temporary guest worker program similar to that proposed by President Bush last year.
The president's plan would allow unauthorized immigrants currently living in the United States to apply for legal status to work and would impose new penalties on companies that knowingly hire illegal workers.
Stewart Verdery is a consultant on immigration issues and a former official in the Homeland Security Department. He told lawmakers that the creation of a guest worker program is an important part of helping law enforcement focus on terrorist and criminal threats coming across the border.
"Providing those who want to work have no prior criminal or terrorism record a means to enter the country legally through ports of entry will make it much more likely that the Border Patrol will be able to locate and arrest criminals and terrorists who will lose their cloak of invisibility that the current situation offers," he said.
But the guest worker proposals have drawn criticism from across the political spectrum.
Immigration opponents are worried about the government's ability to administer a massive new program while immigration advocacy groups are concerned that the plan will not do enough to protect the rights of temporary workers.