The border fence works.

That’s the word from  a U.S. Border Patrol agent in Yuma, Ariz., who says a 20-foot high, cement-filled steel-piped fence is getting the job done when it comes to reducing illegal immigrant apprehenisions in the southwest corner of Arizona.

“A lot of people have the misconception that it is a waste of time and money, but the numbers of apprehensions show that it works,” said agent Michael Bernacke, in a story published this week by the Christian Science Monitor.

That may be in what this agent sees in his small slice of the border, but not all in the law enforcement field are completely convinced about the effectiveness of a border fence within the scope and length of what is mandated by the Secure Fence Act of 2006. U.S. Rep. Silvestre Reyes, D-El Paso, a former U.S. Border Patrol sector chief in the Rio Grande Valley and his native West Texas, has a different take.

In a story published last year in Texas Monthly, Reyes said border fencing in small stretches in mostly urban areas could be effective, but said the vast stretches of fencing in isolated areas as prescribed by the 2006 law would prove to be costly and ineffective. When asked what he expected to hear in an upcoming Republican legislator-chaired hearing on border fencing, (a subject of the magazine story), Reyes said, “A bunch of bull.”

In Brownsville, a former high-level federal law enforcement officer who was also a police officer for many years, told me some border fencing could help in funneling criminal elements, (non-illegal immigrant types crossing to work), into areas where they could be apprehended, but otherwise took a cool view to the notion of miles and miles of such fencing.

“Twenty, 25 years from now, people are going to be clamoring to tear the thing down and asking, `What were people thinking back then when they had it built?’ ” he told me.

What the fence act envisioned was the sort of formidable fencing that divides Israel and the West Bank - and that has been constructed in the Yuma area. Triple and double-layered, and built in the desert and on federal land, the Arizona portion of the fence has seen few obstacles, either in geography or politics.

It’s a different story in South Texas. A meandering river, plenty of native brush, and hundreds of miles of privately owned land seperate the Rio Grande Valley and Mexico. It’s one thing to build fencing in desert land owned by the federal government and quite another to put up such structures on land that in some cases has been owned by the same families for generations.

On flat, hot desert land that is out-of-sight and out-of-mind except for the agents enforcing the law and the immigrants trying to get around them, residents in Yuma apparently give the thing little thought. In Brownsville, where a border fence is plotted out to cut into a university campus and block off the historical view between this city and neighboring Matamoros, this subject carries a completely different  meaning - and impact.

Of course, when politicians in Washington passed the fence law, after failing miserably to enact comprehensive immigration reform, they had no recognition or knowledge of the vast differences in geography, politics and history along the border - not that many of them would care. They don’t. Gaining such understandings is for sissies, apparently, so Homeland Security Secretary Michael Chertoff announced Tuesday that he planned to invoke legal waivers to go around various objections and environmental laws to get more of the fence built as quickly as possible.

Go ahead and put a finger in one stretch of the border, Mr. Secretary, and see something else come out on the other end. 

“For the Yuma sector, the numbers are telling,” said Ken Rosevear, president of the Yuma Chamber of Commerce in the Science Monitor article. “But we all know that once you shut down a pipeline in one area it merely diverts the traffic to somewhere else.”