America's borders with Canada and Mexico stretch more than 6,000 miles. Border Patrol agents are often outnumbered by illegal immigrants and smugglers 100 to one.
"What they'll do is sit out there with spotters and observe us with binoculars," said Chuck Albrecht, a Border Patrol (search) agent. "They'll communicate with each other with cell phones and radios and report to each other when they feel the coast is clear to cross the border."
To help even the odds, the Department of Homeland Security (search) has deployed a vast network of cameras and underground sensors that allow technicians to direct field agents to breaches in security.
But a new government audit says the $240 million system is flawed. At any given time, 20 percent of the surveillance equipment simply doesn't work.
"If those cameras are not working, then people and contraband coming over that border are not gonna get caught," said former Border Patrol bureau chief Carey James.
The Connecticut-based contractor that created and installed the system — International Microwave Co., since bought by L-3 Government Services Inc. (search) of Chantilly, Va. — cut corners and overcharged taxpayers, according to the report.
Customs officials say they are working on repairs, but problems persist. Vastly outnumbered, border officials relying on the system to fill in the gaps say they still feel blind along large sections of the border.
Click in the box near the top of the story to watch a report by FOX News' William La Jeunesse.