A fragile fence: border patrol wages daily battle against smugglers.

YUMA, ARIZ.--The six men jump down from atop the fence on the Mexican-U.S, border in broad daylight, with 200 yards between themselves and the American &cam. A dash over the open space would bring them to a housing development in San Luis, Ariz., a border town where they could easily mix in with the local population. Border Patrol Agents Michael Gramley and Gloriaela Hernandez drive down and park their sports utility vehicle between the would-be migrants and their new life in the United States. The men scramble up the fence, helping each other over until they disappear back into Mexico. They would certainly make another attempt later.

More housing developments such as the one the men were attempting to reach are being built, some coming within 100 yards of the border. "It's just going to make it more problematic for us to patrol this area," Gramley says.

It's a typical busy evening on the U.S. border. During the previous 24-hour period, there were 600 illegal immigrant apprehensions in the Yuma sector alone--double the number of any other sector on the U.S. southern border that day. Of the 143 Border Patrol stations, Yuma is by far the busiest.

And would-be migrants are only part of the story. Earlier in the afternoon, Border Patrol officers received a tip that smugglers were loading illegal drugs a few miles south of Yuma into the back of a hatchback on the banks of the Colorado River. Agents pursued the suspects two miles into the city, where they attempted to ditch the car in a residential driveway. The suspects tried to escape on foot, but were later caught. The man and woman, both U.S. citizens, were arrested and handed over to the Drug Enforcement Agency for prosecution. The bust netted 333 pounds of neatly packaged marijuana worth $267,000.

This year promises to be pivotal for agents, such as those in Yuma. The Bush administration and Congress have shown renewed interest in taking control of the notoriously porous southern border. The Department of Homeland Security has made the secure border initiative its cornerstone. As new immigration legislation winds through the House and Senate this year--and lawmakers debate the 2007 budget request for boosts in both technology funding and manpower--the demand in the United States for cheap labor and narcotics promises to continue unabated.

As the Yuma sector proves, smugglers will search for holes along the 2,000-mile U.S.-Mexico border. The number of apprehensions in Yuma in the fiscal year ending Sept. 30, 2005 totaled 138,486, the highest ever recorded and 40,000 more than the previous year. The number of those caught has tripled since 2002, when 42,654 were apprehended.

Gramley attributes the steady climb to phase I of the Arizona Border Control Initiative, which focused on the West Desert Corridor, west of Nogales, Texas. phase II, was expanded to include the remainder of the Arizona, and is bringing more resources to Yuma, Gramely says.

DHS Secretary Michael Chertoff says the strategy is to roll out resources where they are needed most. Areas with large cities on the Mexican side, such as Tijuana and Nuevo Laredo, are top priority. They provide transportation, hotels and the infrastructure needed for migrants. Desert crossings, such as the Sonora region in Arizona, are natural barriers that can take several days to traverse.

"What we do with the Border Patrol is we prioritize those areas where we are most vulnerable, but we recognize that as we do that, the smugglers will then start to move to other areas which may be a little less hospitable but are still ... not as well protected," Chertoff says.

Unclear is how many immigrants in the Yuma sector manage to slip past the dozens of Border Patrol officers, fences and cameras mounted on towers above the brush.

Jessica Vaughn, senior policy analyst at the Center for Immigration Studies, says the best estimates hold that three-fourths of illegal immigrants crossing the border make it through. There are 8 million to 11 million illegal aliens living in the United States, but those numbers are also ballpark figures, she explains at a transportation and border security conference sponsored by Market Access.

James Jay Carafano, senior fellow at the Heritage Foundation, says the only time these numbers have abated was when the United States went into a recession. The simple fact is the U.S. economy is growing and Central American economies are not. That, coupled with high population growths south of the border, drives those seeking a better way of life.

"Those dynamics aren't going to change," Carafano says at the conference.

At DHS, border issues are now handled at the secretary and deputy secretary level. Power over such programs was previously spread out over several agencies prior to the department's formation. The renewed political will in Washington to take control of the southern border has resulted in competing bills in the House and Senate, several committee hearings and the unveiling of the secure border initiative last fall.

The Bush administration's budget proposal gives significant boosts to the Border Patrol, including $459 million to add 1,500 agents. If the request is approved, the 14,000-member force would see a 42 percent increase in its numbers since 9/11. DHS has also requested $100 million to enhance surveillance and response capabilities. It hosted an industry day in January seeking input on how to use new technologies to meet these goals.

Carafano says the initiative is unlikely to succeed without strong legislative backing, and he doubts anything will pass during an election year. The House version of immigration reform--the Border Protection, Anti-terrorism and Illegal Immigration Control Act of 2005 (H.R. 4437)--does not include a guest worker program, which is strongly favored by President Bush, and certain to be a sticking point with conservatives. Carafano predicts few in the House will be willing to take on that political hot potato with their seats up for grabs in November. Three different immigration reform bills are making their way through the Senate.

Meanwhile, the Border Patrol is looking for a variety of technological solutions to go hand in hand with the boots on the ground, says the agency's chief, David Aguilar. The Border Patrol will rely on industry to propose solutions, he adds. In his mind, illegal immigrants and drug enforcement are not the biggest challenges facing his officers.

"Our top priority, without question, is to keep terrorists and terrorist weapons out of our country" he says.

The Yuma sector, with its diverse terrain, provides a microcosm of the challenges the Border Patrol faces. It has one urban crossing where a Mexican town, San Luis, abuts the border. There are areas on the U.S. side with housing developments built close to the fence making it relatively easy for would-be migrants to make a quick dash into neighborhoods. South of Yuma at the Colorado River, the water is low enough to wade, or for vehicles to ford. To the east, wide-open desert stretches for miles.

Each terrain requires different tactics and technologies, Aguilar says. Near urban areas, agents should be "shoulder to shoulder." In the desert, sensor technology can be used to track suspects for several days until they reach a convenient apprehension point.

In the desert east of San Luis, three thin strands of barbed wire are the only obstructions preventing vehicles or pedestrians from crossing. Waist-high scrub brush affords many potential hiding spots. In Mexico, a well-traveled highway runs parallel to the border. Because the area is several miles from the border towns, and therefore, more difficult to traverse, vehicle incursions here are common.

Recently one smuggler with a carload of immigrants negotiating the desert terrain spotted a Border Patrol truck and floored the gas pedal in a futile attempt to escape. He hit an embankment at 60 miles per hour, totaling the vehicle and injuring several passengers, Gramley says.

A DHS-funded pilot project east of San Luis is placing a 2.5-mile vehicle barrier made of galvanized-steel columns sunk seven feet into the ground. The cylinders are built at different heights to discourage the building of ramps. Resin at their core will prevent smugglers from using welding equipment to dismantle the barriers. DHS is requesting another $50 million to extend the barriers.

The thought of human or contraband smugglers using welding equipment to brazenly destroy the imposing barriers is not farfetched. South of Yuma, where the Colorado River passes through a spot where the Mexico, Arizona and California borders meet, agents placed boulders between the road and 10-foot high brush to prevent vehicles from reaching local roads. Daylight incursions there are more common, because the cars can quickly mix in with the local traffic.

Gramley points out wide gaps where smugglers cleared out the rocks, some of which weigh hundreds of pounds. How they managed to remove them in a matter of hours is mystifying, he admits.

Smugglers have also dug their way under the U.S.-Mexican border to move drugs and people. Nineteen tunnels have been discovered in California and 17 in Arizona since 9/11. Four were exposed in January alone, according to Aguilar.

Also effective are the "mass incursions," Gramley says. They can come any time, day or night. Dozens, and sometimes up to a hundred, illegal aliens flood over the border and dash toward the San Luis housing developments--overwhelming the three or four officers who might be in the vicinity.

"There's no forewarning of it," Gramley says. "We might catch one or two."

The mass incursions, or banzai runs as they're informally called, may include a rocking, when human smugglers known as coyotes bombard trucks with large stones, sometimes covered in oily rags and set alight. The Yuma sector has two "war wagons," trucks specially outfitted with grating to withstand such attacks. The rockings are a diversionary tactic that allows the migrants to make good their escape.

One rock-throwing incident near San Diego turned deadly in January when a Border Patrol agent allegedly shot 18-year-old Guillermo Martinez. He later died of his injuries in Tijuana, and the incident created a diplomatic row between Mexico and the United States. It also resulted in intense criticism in the Mexican press, which has accused the United States of militarizing the border.

At a recent press conference, Aguilar attempted to deflect the criticism by showing U.S. and Latin American journalists how dangerous rock throwing can be. One video taken near San Diego showed coyotes lobbing fist-sized rocks over the fence at agents protected only by plastic shields. One agent inside a truck suffered a severe eye injury. In the last fiscal year, there were 778 assaults against agents, a 108 percent increase from the previous year.

The rockings, and other acts of violence, are an indication of the Border Patrol's effectiveness, both Aguilar and Chertoff say. Mexican criminal gangs who profit from drug and human smuggling are becoming frustrated. But if this is a war, Chertoff vows that the United States will not back down.

"We've got to continue to apply this pressure," Chertoff says. "But we've also got to be prepared to deal very decisively with any violence directed at our Border Patrol agents."

At night near San Luis in the Yuma sector, the atmosphere along the border resembles an eerily quiet war zone as agents in vehicles sit under stadium lights in an expanse across from Mexico. Night-vision cameras perched above 100-foot tall towers are part of the surveillance technology. Civilian employees about 20 miles away in Yuma's communication center monitor a bank of 35 screens.

On one screen, a lone man stands at the edge of a road after emerging from 10-foot high brush, seemingly watching for a safe time to cross. However, he doesn't move for several minutes.

It would be easy for an agent to swoop in and grab the man, but human smugglers are wise to both Border Patrol tactics, and the locations of the cameras, Gramley explains.

The man may be sent there by coyotes to provide a diversion. The camera operator zooms out to take a wider view of the territory, to see if others might be dashing away further down the road.

Meanwhile, another operator guides a Border Patrol truck toward some suspicious movement in the desert where the scrub brush is only knee-high. Two targets appear to be crawling among the sage as the truck zeros in on them.

They turn out to be stray dogs.

Earlier that night, Gramley and Hernandez receive a call from Chief Deputy Leon Wilmot, of the Yuma County Sheriff's Department. While giving a television crew a tour of the border, he has detained six illegal aliens near a county road.

The three men and women sit quietly on the ground as the agents await a larger truck.

Wilmot says control of the border is a federal issue, but it affects his county's crime rates. Incarcerating criminal aliens is costly, amounting to more than $2 million last year. His department only received $200,000 in federal reimbursement.

Agent Hernandez asks the six migrants in Spanish where they are from. Nayarit State, in Mexico, is the answer. They've traveled about 800 miles in search of job opportunities only to be caught. However, none of the six appears to be disappointed. In fact, a few smile and laugh for the television cameras. As Mexican citizens, they can ask for voluntary repatriation. After being processed in Yuma, they will be bused back to San Luis, Mexico, provided that none of them has a criminal record.

If they're unlucky and the processing center is busy, they may have to wait a day. If it's not busy, they could be back in Mexico within a few hours, where they are free to make a second or third attempt. The Yuma sector that day would apprehend 450 other illegal immigrants.

Non-Mexicans caught within 100 miles of the border fall under DHS' new "catch-and-return" policy. The expedited removal process, which flies those designated "other than Mexican" back to their home country, is designed to dissuade would-be migrants from making the long journey. Chertoff said the program is succeeding and there has been noticeable drops in the number of apprehensions.

Meanwhile, Mexicans such as the six caught that night would likely make another attempt.

"Sometimes you'll see the same people three times in the same day," says Hernandez.