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A nervous man with a duffle bag of marijuana. A pack of snorting feral pigs. A woman holding a child's hand. A fluttering, rustling plastic bag. There's plenty for a National Guardsman to look at on a quiet South Texas night.

Customs and Border Protection offered a firsthand look to The Associated Press at what the troops are actually doing, around the clock, in the Rio Grande Valley in south Texas. The sound bite for the tour, often repeated, was that the soldiers are "the eyes and ears for the Border Patrol." And that appears to be the case.

And it now it appears the Guard's role could continue. The one year, 1,200 troop deployment on the border was to expire June 30. But the Obama administration is asking Congress to reprogram $30 million to keep the soldiers there at least through September.

"National Guard support along the Southwest border remains in place," said Department of Homeland Security spokesman Matthew Chandler on Tuesday.

Anticipating the end of their deployment, some units had already started moving out, said Matthew Benson, a spokesman for Arizona Gov. Jan Brewer, who has repeatedly asked the Administration for more law enforcement along the border. Those departures have stopped.

"There has been a pause in the draw-down to enable the Department of Homeland Security to explore an extension to the mission. Nothing further is known at this time," said the National Guard in a written statement from its public affairs office.

"Certainly it's a step in the right direction though we would have preferred the extension would have been longer," said Benson.

Arizona Sen. John McCain said "maintaining the limited National Guard presence currently on the ground is the least the administration can do to protect citizens living in the Southwest border region." McCain and his fellow Republican Arizona senator Jon Kyl have introduced a bill calling for a five year deployment of 6,000 National Guard troops on the border at a cost of $600 million.

During the past year's deployment, each soldier cost taxpayers about $96,000 per year, comparable — with facilities, supplies and other expenses — to Customs and Border Protection agents, according to their respective budgets.

The National Guard troops have augmented the Border Patrol's 21,000 agents by almost 6 percent since July, 2010. The troops serve as lookouts but are not directly involved in actual law enforcement activities. They are credited with helping arrest 17,000 illegal immigrants, almost 6 percent of those caught, according to Customs and Border Protection. The only drug that the National Guard helped seize has been marijuana: 51,000 pounds since July, 2010 — or 2.6 percent of the almost 2 million pounds of marijuana seized by the Border Patrol during that time, said CBP.

But the troops' presence on the border is about more than arrests, seizures and security, said David Shirk, director of the University of San Diego's Trans-Border Institute.

"Symbolism and signaling does matter in politics, and the Obama administration is making an effort to clearly demonstrate to the public that the U.S. border is more heavily fortified than at any point in its history, since for many voters securing the border is an important first step prior to any conversation about reforming U.S. immigration policy," he said.

The modest deployment has been watched warily from Mexico, where the U.S. invasion 165 years ago has not been forgotten.

"The decision of the U.S. government to deploy the National Guard on the border should result in channeling additional resources to prevent illegal trafficking of weapons and cash into our country," said Mexico's President Felipe Calderon's security spokesman Alejandro Poire.

He said the troops should focus on transnational crime, and not be involved in immigration enforcement.

In the Rio Grande Valley, the troops appear largely concerned with their "eyes and ears" responsibility.

They spend 12-hour shifts taking turns sitting 30 feet up in a "Skybox," a moveable watchtower that looks like a bucket truck with a swing arm and an attached phone booth-sized box. Mercifully, the boxes are air conditioned. They're deliberately obvious, poking into the night sky as a deterrent to would-be crossers. Peering toward an orange grove through thermal imaging night vision scopes, dark shadows become shapes, and some of those shapes become suspects.

When a possible illegal immigrant or drug courier is spotted, the soldier in the Skybox radios a colleague below him in the truck and the Border Patrol, which is dispatched to investigate. The soldiers are armed, but they are not allowed to interact with suspects.

"It's obviously more of an adrenaline rush when we're going out there and kicking in doors. Here it's more of a passive role," says Sgt. Ashford. The Guard requested that first names of all soldiers be withheld, citing security concerns.

Texas National Guardsman Cpl. Martinez said he felt compelled by the 9-11 attacks to join the Army and protect his country. After a stint in Iraq, he was sent to the U.S. -Mexico border. He hopes he can stay longer.

"I feel like I'm doing my duty to country, helping keep crime from coming into the United States and that's awesome," he said. "Plus it's never boring. You'd be surprised how much stuff there is to look at."

And even for those with experience in war zones, like Cpl. Martinez, it's not boring.

"I don't know if this person is coming to find a better life or if they're looking for a way to move drugs," he says. "Either way it's wrong. If they want to come here they should do it the right way."

El Paso city councilman Beto O'Rouke is critical of the Guard's role, saying military personnel do not have the training and sensitivity to handle the complex issues that occur at the border.

"There's no place for the National Guard on the border," he says. "We will continue to get these kinds of knee-jerk approaches that do absolutely nothing to resolve legitimate concerns about security until we have real leadership in D.C."

But Texas Congressman Ted Poe says it's simple math: "We need more boots on the ground. The more National Guard troops on the border means the more security we have. Where they're placed, people won't cross."

In a similar initiative under President George W. Bush, more than 6,000 National Guard troops were deployed on the border between 2006 and 2008. National Guard officials said no weapons have been fired in the past year's deployment.