Technology is a major component in securing the border, but spending billions more on equipment and manpower under the Senate immigration bill has some asking whether it's too expensive.
"When it comes to the issue of security, it has been, 'How much more can we do in order to satisfy, in order to accommodate and in order to draw more support for a comprehensive immigration reform package?' " U.S. Rep. Raúl Grijalva, a Democrat, said on the House floor Wednesday. "I understand the logic, but I don't understand at all the overkill and the excess."
The Senate approved an immigration overhaul Thursday, sending the bill to the House.
Earlier in the week the Senate approved a "border surge" amendment from Republican Sens. Bob Corker of Tennessee and John Hoeven of North Dakota that would double the number of Border Patrol agents, add fencing along the U.S.-Mexico borderland and pour billions of dollars into new technology, and do it before any of the 11 million living in the country illegally can adjust to permanent legal status.
Even proponents of the surge are calling it the militarization of the border.
"This is not only sufficient," Arizona Sen. John McCain told CNN, "it is well over sufficient. We'll be the most militarized border since the fall of the Berlin Wall."
Border Patrol staffing, technology and infrastructure have reached historic highs, while levels of apprehensions have fallen to historic lows.
Apprehensions in the Tucson Sector have fallen to the lowest levels since 1993. Meanwhile, the number of agents has more than doubled.
Drug trafficking remains an area of concern, said Tucson Sector Chief Manuel Padilla.
"Until we see that big decline as we are seeing with illegal immigration," he said, "I'll know we are making a big difference."
The Border Patrol strategy a decade ago was to build up technology, personnel and infrastructure. Since the Border Patrol has reached high levels of all three, Padilla said, the strategy released last year shifted. The focus now is information sharing, integration of systems and assets and rapid response.
The number of personnel and range of high-tech equipment used to patrol the roughly 370 miles of the Arizona border have grown over the last five years to include more mobile X-ray vans, portable surveillance systems, vessels and unmanned aircraft.
Under the Senate's immigration bill, the Border Patrol in the Southwest might be infused with thousands of ground sensors, hundreds of fixed and mobile surveillance systems and more aircraft. It also includes adding four drones to a program that has struggled to make full utilization of the systems already in place.
The additional resources that would head to the Southwest border are from a list that McCain said came directly from the Border Patrol.
It would also add 20,000 Border Patrol agents, bringing the total to more than 40,000 - nearly twice the population of Nogales, Ariz.
A few days before the Corker-Hoeven amendment was introduced, McCain said the border needed technology, not more agents as proposed by Texas Sen. John Cornyn.
"The fact is we can get this border secured, and the answer, my friends, as it's proposed in the Cornyn amendment that we hire 10,000 more Border Patrol, is not a recognition of what we really need," he said on the Senate floor. The Cornyn amendment called for 10,000 agents and customs officers.
But when the amendment was filed, McCain told Fox News it was needed to "give people confidence."
Department of Homeland Security officials have said the border "cannot be sealed," but the Border Patrol aims to have 100 percent situational awareness - meaning agents are able to monitor every segment of the border - and that 90 percent of people or traffickers who come through the border are apprehended or turned back to Mexico.
McCain said Thursday before the Senate vote that he can "guarantee" technology will help the Border Patrol achieve that goal because he's seen it work.
The proposal has its share of opponents, not only among pro-immigrant groups but also in the House leadership, where the bill faces an uphill battle.
House Homeland Security Committee Chairman Michael McCaul, R-Texas, said Thursday, "The Senate passed a cart-before-the-horse border-security strategy."
He called the "border surge" a "textbook example of government waste, as it throws arbitrary resources at the border without a long-term national strategy or required outcomes."
A wide range of technology, such as truck-mounted surveillance systems, night-vision goggles, towers with day and night cameras and radar on aircraft, is already being used to help agents determine what's crossing and how they need to respond.
In the Tucson Sector, Padilla said there's enough infrastructure and technology in place in urban areas such as Nogales or Douglas, but challenges remain in rural and mountainous areas.
The surge is an expensive proposition.
The amendment adds $46 billion in security spending, $38 billion more than was proposed originally. About $30 billion would go to hiring the additional agents.
"How will this $5-billion-a-year security buildup be financed?" asked Alex Nowrasteh, an immigration policy analyst at the Cato Institute, a libertarian think thank in Washington, D.C. "They are taking the most expensive and ineffective way to deal with illegal immigration."
McCain has said the expense will be covered with the fees and fines collected from immigrants.
"What the government is doing is spending money they haven't even gotten yet," Nowrasteh said.
"Looks to me like a really good day for contractors," said Robert Lee Maril, a sociologist at East Carolina University who wrote a book about the failures of previous technology programs.
"I'm not saying technology isn't important, but if you don't have the money to pay for gas to keep drones up in the air, why give them more? In some places they still have an old system of sensors on the ground," he said.
Already the federal government spends $18 billion on immigration enforcement, more than on all its other main criminal law enforcement agencies combined, the Washington, D.C.-based Migration Policy Institute reported.
But the construction of infrastructure between the ports of entry has been uneven and tends to happen in bursts of activity in reaction to a perceived need for greater border security, according to the State of the Border report that analyzes the different aspects of the U.S.-Mexico border, including security.
Historically, border-surveillance technology contracting and system performance has had its problems - and its share of the cost.
Between 1998 and 2005, DHS and its precursors spent $429 million on border-surveillance systems that were set off by wind and the movement of animals and trains.
Then, between 2005 and 2011, Homeland Security spent $1 billion on the SBInet virtual fence program before glitches, major delays and the cost prompted officials to cancel it.
And the cost for covering Arizona's border with a mix of technology over several years under a new initiative was estimated at $750 million in 2011.
Homeland Security has also faced criticism for noncompetitive contracting practices, inadequate oversight of contractors and cost overruns. In 2012, funding for border surveillance was cut and CBP was directed to provide a detailed expenditure plan as well as a multiyear investment and management plan.
As with any other type of technology, Padilla said, surveillance equipment used on the border is improving and becoming less expensive.
"The biggest difference was that SBInet was a developing technology looking at this terrain and building technology that fit that need," Padilla said. "With wars overseas and the focus on border security over the years, there's a lot of off-the-shelf technology."
Without it, he said, an agent could spend three hours going to a sensor that went off only to figure out it was a cow.
But technology is only one part of the equation, Padilla said. The infrastructure such as roads and the manpower to respond also are needed.
Determining how much border enforcement has helped reduce the flow of illegal crossers to the current lows is up for debate.
Experts can't determine how much can be attributed to border enforcement or to the worst economic recession since the 1930s.
Some experts argue the real solution to illegal immigration is creating legal paths for workers.
"It's easy for Congress to say we're doing something, putting all this money at the border, but to really fix it, you have to first fix the incentives in the system," said Judy Gans, program manager for immigration policy at the Udall Center for Studies in Public Policy at the University of Arizona. "Right now there's a mismatch of legal channels and what the economy needs."
The bill revamps the temporary guest workers for higher- and lower-skilled workers, but Nowrasteh, of the Cato Institute, doesn't think it goes far enough.
Still, he said, the good portions of the immigration reform bill still outweigh the bad.
On StarNet: Find more recent and archived stories on immigration and other border-related issues at azstarnet.com/border
• The United States has spent nearly $220 billion on immigration enforcement since 1986.
• In 2004, just over 28,000 DHS personnel were assigned to patrol the land and inspect travelers at ports of entry at a total cost of $5.9 billion. By 2011, it had nearly doubled to $11.8 billion and 41,400 personnel.
• Annual appropriations for tactical infrastructure for fiscal 1996-2013 increased from $25 million to $1.5 billion in 2007. But they've fallen every year since, reaching $324 million in fiscal 2013.
• The number of Border Patrol agents in the Southwest sectors grew from 3,496 in 1993 to 18,516 in 2012 - 4,176 in the Tucson Sector.
Sources: Migration Policy Institute, Customs and Border Protection, Congressional Research Service.
Contact reporter Perla Trevizo at email@example.com or at 573-4213. On Twitter: @Perla_Trevizo