SAN DIEGO — A large increase in Border Patrol agents, additional fencing and expanded prosecution of illegal border-crossers contributed to a 20% drop in apprehension of undocumented migrants this year at the U.S.-Mexico frontier, immigration officials announced Tuesday.
Homeland Security Secretary Michael Chertoff said the figure signaled progress in disrupting illegal immigration flows, a key goal of the Bush administration's overall immigration strategy.
But critics and experts said that the border remained dangerously porous and that the numbers did not provide a full picture of illegal activity. Furthermore, they said there was no evidence that the buildup was deterring immigrants.
"The federal government has stood by and done little to strengthen our broken borders or enforce our immigration laws," Sen. John Cornyn (R-Texas) said Tuesday, urging Congress to restore $3 billion in funding for border security that was stripped from a recent defense bill.
Along the Southwest border, apprehensions over the past year decreased in almost every area -- most dramatically in Yuma, Ariz., and Del Rio, Texas, where arrests fell by more than 45%. Near Tucson, the country's busiest illegal immigration corridor, apprehensions dropped 4%, from 392,074 to 378,239, according to recently released data for the 2007 fiscal year, which ended Sept. 30.
Overall, apprehensions decreased from 1,071,972 to 858,638, reaching the lowest point in five years. "It is a fair recognition that we have begun to make some progress and improve over time. What it ought to do is encourage us to step up the tempo," Chertoff told a news conference in Washington.
This year's enforcement buildup boosted the number of Border Patrol agents by more than 2,500, to 14,923, the largest annual increase in the agency's history. About 6,000 National Guard troops also helped guard the frontier.
More than 70 miles of fencing was added, most of it along the Arizona-Mexico border, bringing the total length to almost 155 miles. The department expects to construct an additional 215 miles of primary fencing by the end of 2008.
The biggest apprehension drops, in Yuma and Del Rio, resulted in part because of a zero-tolerance pilot program that requires the criminal prosecution of all illegal border-crossers, authorities said. In most border areas, captured illegal immigrants are quickly returned to Mexico without being formally deported. The new policy, called Operation Streamline, leads to jail terms of as long as 30 days.
The program is scheduled to be expanded next year to other areas in Arizona, though it is unlikely to be implemented along the entire border due to a lack of both detention space and prosecutorial resources.
Bucking the downward trend, the San Diego sector saw a 7% increase in the number of apprehensions. It was the only border area with a jump, leading some experts to believe that immigrants are returning to traditional corridors with easier access to Southern California.
San Diego was once the busiest area for illegal crossings, but the Operation Gatekeeper crackdown in the mid-1990s shifted the immigration flows east to Arizona. Increased enforcement efforts there have created perilous journeys across the desert, possibly forcing migrants to return to safer areas.
Crossing into California from the Tijuana area, where there is an established network of human smugglers and easy access to freeways, could be more enticing for immigrants, say some experts.
"It's a risk-reduction strategy. Even if they cross in the mountains, it's still less risky than the central Arizona desert," said Wayne Cornelius, director of the Center for Comparative Immigration Studies at UC San Diego. "It's easy to hook up with a [smuggler], and it's relatively less dangerous."
Cornelius and other experts believe the lower apprehension figures may be explained by a sluggish U.S. economy that could be drawing fewer immigrants. Also, illegal immigrants make fewer trips back to Mexico due to the increased border enforcement, reducing circular migration patterns, he said.
Times staff writer Tina Marie Macias in Washington contributed to this report.