TIJUANA, Mexico (Reuters) - Mexican grandmother Lucia Angulo has entered the United States illegally so often over the past three decades that she has lost count of how many times border patrols caught her.
But when she left San Diego to visit her dying mother in Mexico last April, she knew it would be harder than ever to return. Nearly a year later, she was still trying.
Angulo is one of hundreds of thousands of illegal immigrants to the United States who have felt the force of tougher U.S. policing, new barriers and record deportations, which have helped cut to nil the net migration flow from south to north, according to a study last year by the non-partisan Pew Hispanic Centre.
That an experienced border crosser like Angulo has struggled to make it back matters not just to her and her family, but to policymakers in Washington as Congress embarks on what may be the biggest overhaul to U.S. immigration laws since 1986.
How effective U.S. border security is in stopping illegal immigration will be vital to convincing lawmakers, mostly Republicans, to back the bipartisan reform and accept some of its more ambitious parts, such as creating a path to citizenship for the estimated 11 million illegal immigrants living in the United States.
President Barack Obama and many other Democrats back the promise of citizenship, partly to placate Hispanic voters who turned out overwhelmingly for them in last November's elections.
After her mother died in the northwestern state of Sinaloa, Angulo went to the border city of Tijuana opposite San Diego. At first sleeping on the beach, she spent months watching the new 16-foot-high (5-metre) ocean fence that divides Mexico from the United States, and waited for fog or rain to give her cover to cross.
In October, Angulo made her move, trying to swim around the border. But the waves were too strong and she gave up, afraid of drowning. On October 30, she was helped over the fence, but a U.S. border patrolman spotted her and she fled back. Hours later, Angulo climbed it again, was arrested and sent back to Mexico.
"It used to be so easy," the 55-year-old said, looking sadly at the steel barrier that extends 330 feet (100 metres) out into the Pacific. Until 2011, a porous fence was all that blocked the beach.
Angulo waited as the weeks passed. Several times a mist rolled in, but she was unable to scale the fence.
Then, just before New Year's, she got word her youngest, U.S.-born daughter Alexis, had tried to kill herself on Christmas Eve.
Determined to see her, Angulo went inland and entered the United States in the California hills near the town of Tecate.
But the Honduran woman she went with got blistered feet and could not continue, and the two turned themselves in.
When she arrived in San Diego 26 years ago, the U.S. border held no real fear for Angulo, who used to cross it twice a year.
She no longer recalls how often she was caught, only that it was "more than 10 times," and that she was never held for more than a few hours. One by one, she brought her three Mexican daughters across, and by 1992 all were with her in San Diego.
U.S. border security was tightened after the September 11, 2001, attacks, and increased further after the 2007-2008 financial crisis, forcing illegal immigrants and smugglers to think harder about how to get over, under or around the frontier.
One way was by sea. In the 2012 fiscal year, 779 people were apprehended illegally crossing the Pacific, up from 230 in 2008, U.S. Border Patrol data show.
Meantime, the amount of marijuana heading north seized on the California coast quintupled from 2010 to 2012, according to figures from U.S. Immigration and Customs Enforcement, or ICE.
Other smugglers chose to dig beneath the border. ICE figures show that 121 tunnels were found between 2006 and 2012, four times the number in the previous seven years.
The change of tactics coincided with greater efforts by the Mexican government to stamp out the drug trade. Migrants were caught in the middle as cartels used them to make money.
Most of the Mexican boats smuggling people and drugs across the border set out south of Tijuana from small fishing villages like Popotla, where the coast is not heavily policed.
A jumble of restaurants, inns and seafood stalls, Popotla hugs a small cove where locals say U.S. gangster Al Capone once used to run contraband. just like in the era of U.S. Prohibition, things can quickly turn violent there.
A few minutes after telling a Reuters reporter that "there are places nearby" better than Popotla to smuggle people or drugs, a local fisherman calling himself Diego got embroiled in a dispute with a group of men in a white van. Moments later, one of the men was shot in the head and killed by an unidentified gunman.
Crossings on the Tijuana-San Diego section of the border are today a fraction of what they once were.
In 1986, when the United States passed a reform that granted amnesty to 3 million illegal immigrants, the Border Patrol arrested 630,000 people crossing into the San Diego area alone.
Last year, fewer 360,000 people were detained across the entire 2,000-mile (3,200-km) border, and only 28,500 in San Diego.
For all the improvements in security, Mexicans no longer have the same economic incentive to move north either.
When she was only 8 years old, Angulo was already picking cotton in the fields of her native Sinaloa.
By the time she left her homeland in search of a better life, she was earning about $3 a day harvesting pumpkins, beans and tomatoes. In San Diego, she was soon being paid more than $3 an hour cleaning rooms in a Holiday Inn.
The economic divide remains large, but it has fallen steadily. U.S. gross domestic product per capita was 11 times higher than Mexico in 1987, the year Angulo came north, World Bank figures show. In 2011, it was only 4.8 times bigger.
The difference between the United States and parts of Central America is more pronounced, and illegal immigrants from countries like Guatemala and Honduras helped make up for a drop in the number of Mexicans arrested on the border last year.
With the western part of the border more secure, traffic has been pushed east, especially into the violent state of Tamaulipas that borders Texas along the Rio Grande river.
On March 10, Erick Sandoval, a Guatemalan living in Austin, Texas, crossed the river north clinging to an inflated tube with other migrants - two weeks after he had been deported to Guatemala City for a 1993 immigration infringement, he said.
From his nine-member group, all but Sandoval were captured, including the guide, he said. Jumping back into the Rio Grande, he nearly drowned before reaching the Mexican side and staggering back to the city of Nuevo Laredo with no shoes.
Nuevo Laredo is a bastion of the Zetas drug gang, which has used the border crossing as an additional source of revenue, kidnapping, robbing or killing migrants at will.
Mexico's National Human Rights Commission, or CNDH, has said the kidnapping of migrants has been on the rise since 2007 - the same year a military-led crackdown on drug cartels began in earnest under former President Felipe Calderon.
CNDH recorded 9,758 victims of kidnapping in a six-month interval straddling 2008 and 2009. The figure rose to 11,333 during the following study period of April to September 2010.
On the same day Guatemalan mechanic Sandoval crossed the Rio Grande, the Mexican army freed 104 Central Americans from a house in Nuevo Laredo, all suspected victims of kidnapping.
Sandoval, 40, who has lived in the United States since he was 20, said he had left a wife and four teenage children in Austin and could not face taking his family back to Guatemala, a country with one of the highest murder rates in the Americas.
"My whole life is (in Austin)," he said from Nuevo Laredo by phone. "So I have to reach my family or probably die trying."
In San Diego, the Mexican daughters of Angulo hope the U.S. Congress will find a way of giving them the same rights as their two half-brothers and half-sister born in the United States. Angulo also has eight grandchildren, all born in the United States, making them citizens.
Perla, 35, the oldest daughter, who like her mother cleans houses for a living, said her greatest hope was to "have her paperwork sorted out" after being unable to study to become a nurse, obtain a driver's license or travel freely as she had hoped.
The mother of three and her sister Nuri, who arrived in the United States as a 7-year-old, both said they felt lucky to have spent most of their lives in San Diego. But they are acutely aware of how the law has left them trapped between two worlds.
"I didn't decide to come here," said Nuri, 29, a mother of two who left school early to clean houses. "I don't know about Mexican history. I know the history of the United States and the presidents here. I feel awful to have grown up here and to know all about the history, and to love the country but not be from the country. Because I have nothing, I don't exist."
But the family is not apt to dwell on its problems.
Her sister Alexis, 22, is now expecting a second child.
As a fog descended on Tijuana beach on the evening of March 12, Angulo again climbed over the border fence, slipping away into the darkness to rejoin her family.
"I'm never going back to Mexico again unless I have papers," she said. "Only if they catch me. I'm from San Diego."
Additional reporting by Tim Gaynor in Phoenix; Editing by Mary Milliken and Peter Cooney