Debate over the construction of a Southwest border fence continues to divide Congress. But the disagreement isn't over whether to build the fence; nearly all of Congress, including all Presidential candidates, favors its construction.  The bone of contention is over what type of fence and how much to build.

The fiercest disagreement is between two members of congress on the same side of the political isle: Texas Senator Kay Bailey Hutchinson (R) and California Representative Duncan Hunter (R).

Since the Secure Fence Act - which originally required 850 miles of double-layered fencing along the Southwest border - passed the House and Senate in 2006, Hutchinson has advocated for more flexible standards. She succeeded in modifying the fence-building requirements in a provision of an omnibus spending bill (HR 2764) passed this past December.

Hutchinson's amendment strikes the requirement for the second layer of fence known as the Sandia fence, an angled two-piece fence built 20-100 feet apart from the primary fence to leave space for an access road. Border security agents patrol the roadway in sport utility or all terrain vehicles. The Sandia fence was constructed along 9.5 miles of the San Diego border. Instead of a double-layer, Hutchinson's amendment requires reinforced fencing (meaning buttressed to ensure stability), while granting the Secretary of DHS the discretion not to install fence at a particular location.

Hunter, a staunch advocate of the double-layered fence, feels the construction of the fence has taken far too long and is outraged about Hutchinson's changes. In the wake of her amendment, Hunter introduced legislation to restore the double layer requirement and put a deadline on the completion of 700 miles of fence.

In a press statement issued on February 11th, Hunter asserted that "...single-layered fencing and vehicle barriers do little, if anything, to stop illegal immigration" while crediting San Diego's double-layered border fence for reducing the smuggling of people and narcotics.

But Hutchinson refutes the necessity of the second layer. A press release on her website states that Customs and Border Protection (CBP) indicated that double layer fencing is not the most effective in all cases. It also costs twice as much as the primary layer of fence.  

A Congressional Research Study (CRS) support one of her claims, noting that primary fence costs roughly $400,000 per mile versus $800,000 per mile for the double layer.  Intuition supports these estimates.  

The real question is: Does a double-layer fence provide twice as much security to warrant the spending?

A study of the San Diego border by CRS (see attachment) concluded that the most effective deterrent of illegal immigration lay in the installation of border fencing in combination with an increase in agent manpower and technological assets. In 1994, U.S. Border Patrol (USBP) began Operation Gatekeeper, a fancy way of stating a planned increase in agent manpower and technology. Under Operation Gatekeeper, between October 1994 and June of 1998, the San Diego sector saw the following increases in resources:

• USBP agent manpower increased by 150%;
• Seismic sensors deployed increased by 171%;
• Vehicle fleet increased by 152%
• Infrared night-vision goggles increased from 12 to 49
• Permanent lighting increased from 1 mile to 6 miles, and 100 portable lighting platforms were deployed
• The Helicopter fleet increased from 6 to 10.

The operation appears to have been successful.  Since the program became fully implemented in 1998, the number of apprehensions in San Diego decreased dramatically, proving the effectiveness of the new human and technological barriers. However, because the number of attempted border crossings in any given year remains unknown, apprehensions rates may not be an accurate way to discern a policy's effectiveness. Moreover, one individual may be apprehended multiple times, thereby skewing the numbers.

Some data remains trustworthy, however.  Prior to the start of Operation Gatekeeper in 1994, the Army Corps of Engineers constructed a 14-mile single line of fencing to prevent illegal crossovers into San Diego.  Based upon data collected prior to and after 1994, CRS concluded: "The primary fence, by itself, did not have a discernible impact on the influx of unauthorized aliens coming across the border in San Diego."  

The figure below depicts the massive decrease in apprehensions at the San Diego border following the implementation of Operation Gatekeeper.  While the program was effective in deterring illegal immigrants in San Diego, there's no way of knowing if those attempting to cross into the U.S. simply shifted their attempts east by 20 or so miles, where security was more lax.



Despite the failure of the single-layer fence to secure the border in San Diego, the USBP argues for the mixed approach and flexibility that Hutchinson's amendment supports. They stated in front of Congress that: "It's not about fences. It's not about Border Patrol agents. It's not about technology. It's about all of those things."

Homeland Security Secretary Michael Chertoff agrees, stating his preference for technology and manpower over physical walls.  "We think a virtual fence, which includes physical fencing in the appropriate places but also looks to 21st Century technology, is the most cost-effective and quickest and best way to get control of the border."

Border fencing is a relatively new issue, so a lack of information concerning its overall costs and benefits plagues policy makers. However, given the San Diego study and position of the U.S. Border Patrol, the double-layer fence doesn't seem to be the illegal immigration panacea that Hunter purports it to be. With the high costs of the second-layer, and the uncertain benefits, a single layer fence, combined with more manpower and technology, seems a more pragmatic way to proceed until additional data becomes available. If the data indicates that proper border security cannot be obtained without another layer of fencing, then we can build the second layer.  Until then, it doesn't make much sense to spend the extra $280 million on a second layer that may or may not work.  For now, that money may be better spent on manpower and technology.