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Vietnam: Fencing in the North

With the presidential campaign barely more than a year away, there are signs that Mr. Johnson is planning to add something new to the war effort which could eventually change the nature of the Vietnam struggle. The new factor is a “barrier” of electronic devices around Vietnam to monitor infiltration of men and supplies from North Vietnam, Laos and Cambodia, and to permit rapid border enforcement. If the electronic wall were to curb infiltration, the residual arguments for continued bombing of North Vietnam would lose whatever validity they might still have.

The impression grows that under present strategy, neither the many battles in the South nor the air war against the North are going to bring an end to the fighting. One no longer hears much about that “light at the end of the tunnel” which glimmered fitfully last fall. General Westmoreland has sent Washington his estimates of the number of additional American troops he could use, mostly for more search and destroy operations. These are said to run from one more division up to four or five, in descending order of priority. But there is no evidence that General Westmoreland guarantees that any number of additional troops will produce victory within a year or 15 months. The retraining of South Vietnam’s army (ARVN) for “pacification” duty has turned out to be a far longer-term project than the optimists expected last fall, and one begins to hear about all sorts of new organizational schemes to make better use of ARVN’s manpower.

The bombing campaign against North Vietnam has run for nearly 30 months. Well over $1 billion worth of American aircraft has been lost to enemy fire or in accidents; at least another $1 billion in ordnance has been dropped on or shot at North Vietnam; more than 500 American pilots have been killed or captured; most of the North's industry has been hit and at least partially destroyed, and its roads, railroads, bridges and waterways are under constant attack. Yet the enemy force in South Vietnam keeps growing slowly, according to published intelligence estimates. The intensity of conflict in the South is also growing. The North Vietnamese leaders seem fully prepared and able to sit out another year or more of bombing, both to prove that they will not submit to coercion and to see what the American presidential election will bring. Pondering this, the President must at times be tempted to believe that “more of the same” will bring only more of the same – another year or more of “this bloody impasse,” as he called it last month, with a settlement not perceptibly nearer. Not the best record to run on.

But Mr. Johnson believes that a negotiated settlement is no more attainable than a military victory in the short run. In the opinion of the officials who estimate Hanoi’s intentions, the North Vietnamese government would agree to “talks” if the bombing of North Vietnam were stopped. They doubt, however, that the “talks” would lead to “negotiations” during which Hanoi would back away from any of its aims – certainly not until after the US elections. The estimate of the Joint Chiefs of Staff, which the President can hardly ignore when he has troops in the field, is that Hanoi would take military advantage of the cessation of bombing to increase infiltration of men and supplies in the South, in hopes of achieving a major tactical victory that would have maximum political impact in Washington and Saigon. So when the military are asked about ending the bombing, they growl “over our dead bodies,” and they mean that literally.

Thus, the President is told that the safest way to fight the war in the South is to continue bombing the North, relentless pressure countering relentless pressure. At the same time, he is also being given a highly unfavorable assessment of the bombing as a costly and inefficient counterinfiltration weapon. (According to the air force chief of staff himself, most bombing raids against North Vietnam achieve a “700-foot CEP” – circular error probable. This means that only half the bombs drop within 700 feet of their targets.) Moreover, persistent bombing is poisoning relations between the US and other nations, particularly the Soviet Union, and contributes to holding up such vital matters as talks on limiting deployment of anti-ballistic missiles or a Middle East settlement. Nor is it bringing Hanoi to the conference table. Moreover, Mr. Johnson is told it is morally repugnant to a lot of Americans who are not the demonstrating sort. Curiously enough, this assessment is coming from the Pentagon, although not from the Joint Chiefs of Staff. It is held not only by Department of Defense civilians, but by some lower-grade officers.

For several years, the Defense Department has considered various schemes for blocking the infiltration from North Vietnam by physical barriers. Most were discarded as too static, too costly in terms of manpower, and not likely to have the same military or (it was hoped) political advantages as bombing. The military, in particular, were opposed to the barrier plans. But the idea remained as a possible alternative to the bombing strategy, and as possible insurance against the reintroduction of infiltration following any political settlement. For these reasons, a major research program named “Practice Nine” was started by Defense Secretary Robert S. McNamara last year to determine whether new detection and warning devices could be developed that would make a barrier “cost effective.”

“Everybody and his brother,” according to one research official, has been called in to deliver opinions on the feasibility of the sensor technology required and on the “trade-offs” between a barrier and bombing, as well as to do the engineering. Combinations of airborne and ground-based sensors have been studied to determine the best way to detect foot infiltrators, bicycle and pack animal traffic under dense jungle canopy in wild, rough terrain. When the sensors detect such traffic, they would alert observation posts or planes which could order artillery fire, air strikes and helicopter-borne troops to stop the infiltration. Barbed wire, minefields, strongpoints and other standard barrier devices would be used where the terrain permitted. Where it did not, mine-activating sensors could be installed along infiltration trails, along with sensors to call in air strikes and reaction forces.

An electronic fence of this sort would make use of improved night observation devices using light intensification techniques; personnel detection radars which see moving targets by means of the Doppler shift, and which have been used successfully at ranges of several miles to aid in protecting isolated Special Forces camps in Vietnam; seismic detectors that can be remotely placed to pick up ground tremors caused by marching men; magnetic detection devices; infrared sensors; ultraviolet sensors; acoustical amplifiers; “electric eye” beam-breaking devices and other gadgetry. Some would have a radio link to rapid data-processing equipment, which would analyze the patterns for estimates of the amount and kind of traffic.


Where Would It Be Built?

Army studies have determined that a “reasonably impermeable barrier” using this sort of technology could be constructed at a cost of $1 million a mile, including manning costs which make up 80 percent of the total. And even if the cost estimate doubled, officials have said, it would be cheaper to build a barrier around the 600 miles of South Vietnam than to lose another 600 attack aircraft over North Vietnam, at $2 million a plane plus the cost of bombs dropped.

The same sensor technology can be used to improve the efficiency of search and destroy forces in South Vietnam, which one defense official describes as very low. By helping to pinpoint enemy forces, camps and tunnels, he said, the technology “can improve search and destroy by a factor of 10.”

Advances in sensor technology, notwithstanding, the barrier plan remains controversial. Some find repugnant the concept of a “Berlin wall” built by the United States, although the arguable point is made that the Berlin wall was designed to keep people in while this wall would be designed to keep them out. The military are no longer so strongly opposed to the idea, but they don’t want to take men from search and destroy operations and tie them down guarding the barrier. It is thought that a barrier of any length would require three to four divisions of airmobile troops (more than two divisions are now on border duty). Also, they believe the barrier should stretch from the South China Sea across the northern tip of South Vietnam and then on across Laos to the Mekong River, instead of ending at the Laotian border. But that is ruled out; the Laotian government firmly opposes the plan. An alternative is to turn the barrier south along South Vietnam's western boundary. But this is very rough territory, where installation of the barrier would be more difficult and its effectiveness more open to question. Finally, some of the sensor devices will not be available for at least a year, if then. Technologically, they present “magnificent problems,” one official notes.

Nevertheless, the Administration apparently is preparing to field-test the electronic barrier on a major scale, beginning just south of the demilitarized zone between North and South Vietnam. Already, Marines have cleared a seven-mile strip between Gio Linh and Gon Thien which is being widened to 500 yards. This will be sowed with mines, barbed wire and sensors and covered by concentrated artillery. According to reports, the strip will next be extended four miles from Gio Linh to the coast, then westward. It might then be carried south along the boundary.

Officials think that, using present technology, a barrier covering the major infiltration routes can be installed within a year. If this is done, and it proves effective, the President will perhaps be in a position to deescalate, then stop the bombing without risking major trouble in the South from infiltration. This might be the formula to solve the current impasse, and, conveniently, it would be available for use just about the time the presidential campaign picks up momentum during the fall of 1968.

In the 17th century the rival war lords of the Trinh and Nguyen families, rulers respectively of North and South Vietnam, fought constantly with each other. But the Trinh, although stronger, were unable to overcome the Nguyen and seize the South. Historians attribute the successful southern defense in part to two huge walls built across the coastal plains by the Nguyen in the 1630’s, near the narrow waist some 25 miles north of the present demilitarized zone. That division of Vietnam, according lo Bernard Fall, lasted 150 years. But it did not bring peace. The learning curve in Vietnam is very flat.

Andrew Hamilton is a writer on military affairs for Newhouse newspapers.

This article originally ran in the July 8, 1967, issue of the magazine.