Trancredo famously brought up the specter of terrorists crossing the southern border in this ad:

And the boyz at Fox Noise have turned up the fear meter on more than one occasion:

But a new report from the General Accounting Office sheds new light on exactly where the nation's greatest border security threats exist ....and they aren't along the much patrolled southern border...but our remote and unmonitored northern one.  

GAO investigators identified numerous border security vulnerabilities, both at ports of entry and at unmanned and unmonitored land border locations between the ports of entry. In testing ports of entry, undercover investigators carried counterfeit drivers' licenses, birth certificates, employee identification cards, and other documents, presented themselves at ports of entry and sought admittance to the United States dozens of times. They arrived in rental cars, on foot, by boat, and by airplane. They attempted to enter in four states on the northern border (Washington, New York, Michigan, and Idaho), three states on the southern border (California, Arizona, and Texas), and two other states requiring international air travel (Florida and Virginia). In nearly every case, government inspectors accepted oral assertions and counterfeit identification provided by GAO investigators as proof of U.S. citizenship and allowed them to enter the country. In total, undercover investigators made 42 crossings with a 93 percent success rate

In its most recent work, GAO shifted its focus from ports of entry and primarily performed limited security assessments of unmanned and unmonitored areas between ports of entry. The names of the states GAO visited for this limited security assessment have been withheld at the request of CBP. In four states along the U.S.-Canada border, GAO found state roads that were very close to the border that CBP did not appear to monitor. In three states, the proximity of the road to the border allowed investigators to cross undetected, successfully simulating the cross-border movement of radioactive materials or other contraband into the United States from Canada. For example, in one apparently unmanned, unmonitored area on the northern border, the U.S. Border Patrol was alerted to GAO's activities through the tip of an alert citizen. However, the responding U.S. Border Patrol agents were not able to locate the investigators and their simulated contraband. Also on the northern border, GAO investigators located several ports of entry in one state on the northern border that had posted daytime hours and were unmanned overnight. Investigators observed that surveillance equipment was in operation, but that the only preventive measure to stop an individual from crossing the border into the United States was a barrier across the road that could be driven around. GAO also identified potential security vulnerabilities on federally managed lands adjacent to the U.S.-Mexico border. GAO concluded that CBP faces significant challenges on the northern border, and that a determined cross-border violator would likely be able to bring radioactive materials or other contraband undetected into the United States by crossing the U.S.-Canada border at any of the assessed locations.

GAO - "BORDER SECURITY: Summary of Covert Tests and Security Assessments for the Senate Committee on Finance, 2003-2007"

But due to political considerations the allocation of security assets along the two borders has always been disproportional.  

Regarding land ports of entry, the United States shares over 5,000 miles of border with Canada to the north (including the state of Alaska), and 1,900 miles of border with Mexico to the south. Individuals attempting to legally enter the United States by land present themselves to a CBP officer at one of the 170 ports of entry located along these borders....

... The U.S. Border Patrol, a component of CBP, patrols and monitors areas between ports of entry. However, given limited resources and the wide expanse of the border, the U.S. Border Patrol is limited in its ability to monitor the border either through use of technology or with a consistent manned presence. Commensurate with its perception of the threat, CBP has distributed human resources differently on the northern border than it has on the southern border. According to CBP, as of May 2007, it had 972 U.S. Border Patrol agents assigned to the northern border and 11,986 agents assigned to the southern border. The number of agents actually providing border protection at any given time is far smaller than these figures suggest. As mentioned above, in the September 2007 hearing on border security before your Committee, a CBP official stated that roughly 250 U.S. Border Patrol agents were patrolling the U.S.-Canada border at any given time--about a quarter of all agents reportedly assigned to patrol the northern border during that period.

So with a greatly undermanned force along the 5000 mile Canadian border, security has been lax at best.

According to CBP, the ease and speed with which a cross-border violator can travel to the border, cross the border, and leave the location of the crossing are critical factors in determining whether an area of the border is vulnerable. We identified state roads close to the border that appeared to be unmanned and unmonitored, allowing us to simulate the cross-border movement of radioactive materials or other contraband from Canada into the United States. For example, on October 31, 2006, our investigators positioned themselves on opposite sides of the U.S.-Canada border in an unmanned location. Our investigators selected this location because roads on either side of the border would allow them to quickly and easily exchange simulated contraband. After receiving a signal by cell phone, the investigator in Canada left his vehicle and walked approximately 25 feet to the border carrying a red duffel bag. While investigators on the U.S. side took photographs and made a digital video recording, the individual with the duffel bag proceeded the remaining 50 feet, transferred the duffel bag to the investigators on the U.S. side, and returned to his vehicle on the Canadian side. The set up and exchange lasted approximately 10 minutes, during which time the investigators were in view of residents both on the Canadian and U.S. sides of the border. According to CBP records of this incident, an alert citizen notified the U.S. Border Patrol about the suspicious activities of our investigators. The U.S. Border Patrol subsequently attempted to search for a vehicle matching the description of the rental vehicle our investigators used. However, the U.S. Border Patrol was not able to locate the investigators with the duffel bag, even though they had parked nearby to observe traffic passing through the port of entry.

We also identified several ports of entry with posted daytime hours in one state on the northern border. During the daytime these ports of entry are staffed by CBP officers. During the night, CBP told us that it relies on surveillance systems to monitor, respond to, and attempt to interdict illegal border crossing activity. For example, on November 14, 2006, at about 11:00 p.m., our investigators arrived on the U.S. side of one port of entry that had closed for the night. Investigators observed that surveillance equipment was in operation but that the only visible preventive measure to stop an individual from entering the United States was a barrier across the road that could be driven around. CBP provided us with records that confirmed our observations about the barrier at this port of entry, indicating that on one occasion a cross-border violator drove around this type of barrier to illegally enter the United States. Although the violator was later caught by state law enforcement officers and arrested by the U.S. Border Patrol, we were concerned that these ports of entry were unmanned overnight.

Contrary to the situation on the northern border, the southern border was found to be highly fortified. And while the GAO inspectors were able to find some holes in security, some were due to conflicting jurisdictions on tribal and federally managed lands.

In contrast to our observations on the northern border, our investigators observed a large law enforcement and Army National Guard presence near a state road on the southern border, including unmanned aerial vehicles. On October 17, 2006, two of our investigators left a main U.S. route about a quarter mile from a U.S.-Mexico port of entry. Traveling on a dirt road that parallels the border, our investigators used a GPS system to get as close to the border as possible. Our investigators passed U.S. Border Patrol agents and U.S. Army National Guard units. In addition, our investigators spotted unmanned aerial vehicles and a helicopter flying parallel to the border. At the point where the dirt road ran closest to the U.S.-Mexico border, our investigators spotted additional U.S. Border Patrol vehicles parked in a covered position. About three-fourths of a mile from these vehicles, our investigators pulled off the road. One investigator exited the vehicle and proceeded on foot through several gulches and gullies toward the Mexican border. His intent was to find out whether he would be questioned by law enforcement agents about his activities. He returned to the vehicle after 15 minutes, at which time our investigators returned to the main road. Our investigators did not observe any public traffic on this road for the 1 hour that they were in the area, but none of the law enforcement units attempted to stop our investigators and find out what they were doing. According to CBP, because our investigators did not approach from the direction of Mexico, there would be no expectation for law enforcement units to question these activities.

In another example, on January 23, 2007, our investigators arrived on federally managed lands adjacent to the U.S.-Mexico border. In this area, the Rio Grande River forms the southern border between the United States and Mexico. After driving off-road in a 4x4 vehicle to the banks of the Rio Grande, our investigators observed, in two locations, evidence that frequent border crossings took place. In one location, the investigators observed well-worn footpaths and tire tracks on the Mexican side of the river. ... Our investigators were in this area for 1 hour and 30 minutes and observed no surveillance equipment, intrusion alarm systems, or law enforcement presence. Our investigators were not challenged regarding their activities. After performing our limited security assessment of these locations, investigators learned that a memorandum of understanding exists between DHS (of which CBP is a component), the Department of the Interior, and the Department of Agriculture regarding the protection of federal lands adjacent to U.S. borders. Although CBP is ultimately responsible for protecting these areas, officials told us that certain legal, environmental, and cultural considerations limit options for enforcement--for example, environmental restrictions and tribal sovereignty rights.

As evidenced by this report from the GAO, while the southern border is far from airtight, and for bureaucratic reasons some areas are not as highly scrutinized as others, the comparison between the actual probabilities of a terrorist or other national security threat penetrating the southern as opposed to the  northern border are as different as night and day.  

While vast expanses of the northern border go totally un-secured or are guarded only by day, or by traffic gates that can be driven around, the southern border contains walls, barriers, vast number of Border Patrol Agents, and National Guard, unmanned drones and high-tech surveillance equipment.  All in attempts to keep out and control the flow of people looking to work.  While to the north, those wishing to do real harm can walk right in.

But I guess those guys that FOX tells us about  from "Cairo, or somewhere else in the Mid-East" who go to Mexico to "get acculturated and learn Spanish of the kind spoken in Mexico" ...to sneak over the border since "you can't tell the difference" between an Arab and a Mexican if you "strip em down and dress em up"  ...and since it's so easy for "Arabs to acculturate in Mexico because up to 1942 Islam ran the Iberian peninsular"  ...just aren't aware of the fact that the Canadian border is like a sieve and they could just walk right through any time they wanted.  Or maybe they're just too stupid to figure that out ...being brown and all.....   Jeez.

Cross-posted at: The Sanctuary