A.E. Araiza, Associated Press
Shanti Sellz, at left in denim jacket, and Daniel Strauss, center, listen to attorney Isabel Garcia.

TUCSON, Ariz. — Emil Hidalgo-Solis couldn't stop throwing up. His diarrhea was bloody. His feet blistered. He had staggered through the desert, stumbled across the border, gulped contaminated water from a slimy cattle trough.

On this scorching day — in the hottest July in local history — Hidalgo-Solis seemed doomed to be among hundreds who died trying to enter the United States from Mexico last year.

He collapsed in a ditch. He and two others among the 10 immigrants could go no farther.

Then, from nowhere, a truck appeared. On its side, in big letters, was the word "Samaritan." Inside were members of a faith-based group called No More Deaths, offering water, food and a ride to a doctor. They took the three to a makeshift camp, and then set out for a church where a doctor and a nurse would meet them.

Daniel Strauss was at the wheel of the old Subaru GL wagon, with Shanti Sellz beside him. The air conditioner cooled the car as they rode in silence. One of the men offered to hide.

"We told them no, please sit up straight and buckle your seat belt," Sellz recalls.

But then, Strauss looked back and saw that they were being followed by a Border Patrol vehicle. The officers trailed them for maybe 13 miles before pulling them over; they stopped, shutting down their engine and letting the heat outside creep in.

Strauss gazed at his three passengers, cowering in the tattered black clothes they had hoped would help them evade detection.

There was nothing we can do for you, the volunteers said — you are going to be arrested. "We had warned them before they got evacuated what the rules were, and that we couldn't hide them in any way," Strauss says. "We did our best to try to tell them it was going to be all right, but we didn't know if it would."

The officer asked, "Are your three passengers illegal?"

"I don't know," Strauss said.

Then, Sellz recalls, the officer poked his head into the car and asked the passengers: "Do you guys speak English?"

No one answered.

"The officer turned to us and said, 'Those guys are illegal and you know it.' "

Two more Border Patrol vehicles arrived. They arrested Hidalgo-Solis and his companions.

But they also arrested Strauss and Sellz.

"Are you really arresting me?" Sellz recalls asking, in amazement.

"I know you guys are good people but what you're doing is illegal," she was told.

In Washington, senators are engaged in a bitter debate over immigration reform; the House of Representatives has already passed a bill that would set penalties for anyone who knowingly assists or encourages illegal immigrants to remain here.

What these lawmakers decide, from the cool, marbled halls of Capitol Hill, is a matter of life and death to people like Emil Hidalgo-Solis, thousands of miles away.

And it is a matter of high import to many others. When Hidalgo-Solis stumbled through the Sonora desert last summer, he stumbled into a strange dance:

Rifle-bearing Minutemen staked out the migrants, urgently calling law enforcement when they spotted suspicious groups; volunteers in cars marked with huge red crosses delivered tanks of water to supply posts marked with 30-foot blue poles; border patrol agents rounded up migrant after migrant, chasing them out of the bushes and arroyos, scattering them about on what has become the most deadly trail into this country.

Amid the Gila monsters and towering saguaros arise fundamental issues this nation is now struggling to resolve: security and terrorism, labor demand and globalism, the teachings of Jesus to be merciful and the language of federal law, which by its very nature must serve as a gatekeeper for the nation's border.

In November, President Bush went to Tucson to pitch his own proposed immigration reforms, which among other things would beef up laws to prosecute those who help illegal immigrants.

He said the United States "has always been a compassionate nation that values the newcomer and takes great pride in our immigrant heritage," but illegal immigrants were violating U.S. law. "The American people should not have to choose between a welcoming society and a lawful society. We can have both at the same time."

Sellz and Strauss are testing that thesis. They are slated to go to trial on April 25 on felony charges of knowingly and intentionally conspiring to transport an illegal alien, and with transporting an illegal alien, knowing and in reckless disregard of the fact that he had come to, entered and remained in the U.S. in violation of law.

If convicted, they could face up to 15 years in federal prison.

They have declined two different plea offers, one that came just a week after their arrests, that would have wiped their records clean in exchange for a no-contest plea. They insist that in transporting sick people, they were not in any way breaking the law.

"Humanitarian work needs to be applauded, not prosecuted," says Strauss.

This is not the first time that the border has seen this kind of conflict. In 1982, the Southside Presbyterian Church in Pima County declared itself a sanctuary for Central American refugees. Other churches across the country — Catholic, Presbyterian, Methodist, Jewish, Quaker and Mennonite — joined the effort, providing transportation, housing, food and clothes to Salvadorans and Guatemalans fleeing persecution.

The Justice Department soon stepped in.

Sanctuary members argued that they were legally and morally obliged to help people fleeing persecution and death squads. They said they were following their religious convictions and that the refugees deserved political asylum. Even the prosecutor conceded that the immigrants were simply seeking jobs.

But in May 1986, after a six-month trial, eight Sanctuary members were convicted of conspiracy or other charges involving illegal entry of aliens. All received probation.

The new activists were organized by some of the leaders of the earlier Sanctuary movement, and they say there are merely responding to a humanitarian emergency.

"We were seeing increasing numbers of people dying in our desert. We asked ourselves, 'What's our responsibility as people of faith?' " says Presbyterian pastor John Fife, who was among those convicted in 1986.

In 2005, two records were broken: 1.2 million people were arrested trying to cross the border, up from 1.16 million in 2004; and 415 people perished trying to make that crossing, far higher than the previous year's total of 330 and surpassing the high mark of 383 set in 2000.

Almost half of all of the arrests and deaths were in the Tucson region, south of Arizona, in the Sonora Desert where Sellz and Strauss found Hidalgo-Solis.

The region became the busiest migrant corridor after the federal government launched border crackdowns in 1993 and 1994, erecting a steel wall made of surplus Navy landing mats, adding patrols and installing lights and motion sensors south of San Diego for Operation Gatekeeper, and instituting Operation Hold The Line, a 20-mile blockade of agents along the border between El Paso, Texas and Ciudad Juarez.

The programs didn't reduce the flow of illegal immigrants, but it did force migrants and smugglers inland through more dangerous, sparsely populated highlands and deserts.

"While migrants have always faced danger crossing the border and many died before INS began its strategy, the strategy has resulted in an increase in deaths from exposure to either heat or cold," said the General Accounting Office in 2001, citing Border Patrol data.

In 2000, volunteers from about a dozen congregations including Protestants, Catholics, Jews, Quakers and United Church of Christ, founded Humane Borders to try to reduce these deaths.

They set up water stations, more than 70 large blue tanks topped with tall flags, and persuaded Border Patrol chiefs to not stake them out. A series of other programs soon began, including posters and handout maps of the region, medical centers and search teams.

Even local government has chipped in, providing annual grants of $25,000 to Humane Borders.

"It is a humanitarian issue where you have to draw on your own religious beliefs to try to prevent death," said Pima County Supervisor Richard El.

There had been indications that the Border Patrol might crack down on No More Deaths. In August 2004, Michael Nicely, a 25-year veteran agent, took over as chief of the Border Patrol's Tucson sector.

Nicely warned organizers that his agents might keep watch over their aid camps, and that if they transported people they risked arrest, Fife said.

If the volunteers' "true intention is humanitarian, an agent will be in shouting distance" — which would be the most effective way to get emergency medical care for an ill immigrant, Nicely said. "I have no interest in keeping them from providing humanitarian aid. Quite the contrary."

But he said he's made it clear to Fife and others that "there are no free zones in the Tucson sector. There is not an avenue of ingress where Border Patrol agents do not patrol."

"It doesn't matter who you are, humanitarian, Minuteman or just a citizen, if you're transporting an illegal alien then you're breaking the law. You're smuggling an illegal alien," says Johnny Bernal, a supervisory border patrol agent in Tucson.

This is fine with Chris Simcox, founder of the Minuteman Civil Defense Corps, which has gained attention with its civilian patrols along the border.

"I think once and for all, hopefully, this will be a deterrent to break up this underground railroad," he said. "These people have a network with churches as sanctuaries to help people enter our country illegally. How do they know they're not assisting a rapist or criminal?"

But Fife, the activist minister, says instead of arresting volunteers, the Border Patrol should negotiate with them.

Regardless of the outcome of the case against Sellz and Strauss, he said, "we're not going to stop helping these people. We can't stop.

"As people of faith and conscience, with all of those poor hardworking God fearing desperate migrants dying in the Sonora desert for no reason at all except for a failed border strategy, we've got to be out there providing whatever humanitarian aid we can."

Before they left for the church with the three Mexicans, Sellz and Strauss followed procedure and got the go-ahead from a lawyer. During the past two summers, Sellz says she transported eight or 10 other people for medical care without incident.

And so they were shocked to find themselves locked in cells for two days last July.

Sellz — a 23-year-old former Americorps volunteer who has interned with an ecological preserve in Ecuador and worked in food co-ops — grows very worried when she considers the prospect of 15 years in federal prison.

Daniel Strauss, 24 and newly married, is more sanguine. When he was in college, he visited the U.S.-Mexico border as part of a sociology course on immigration. "I saw how hard of a life it was for them, to make a living, to be with their families. When I found out what they had to go through just to get into this country, to make an honest living, it amazed me," he said.

This has been an exciting time, he says. He's famous in the world of migrants, his smiling face appearing on Spanish-language television news broadcasts so frequently that he's often recognized at the immigrant center where he works in Jackson, Wyo.

Both say regardless of the consequences, they intend to return to the Arizona next summer, and resume their work with No More Deaths.

"I do not, in no way, think what we're doing is wrong," says Sellz.