The sun inches over the mountains of the Arivaca Valley, where Arizona's desert landscape is as beautiful as the tourist brochures promise. Rugged rock formations glint in the morning light. Coyotes and roadrunners trot under giant cacti.

Arivaca is a national refuge; cars are banned here. But this ruling doesn't hold for the US Border Patrol. Motorcycles and jeeps roar through the desert, a prison van approaches, helicopters circle in the sky. The name the Border Patrol chose for its mission here is an apt one -- "Dusty." The helicopters dive sharply and cover a small group of people in a cloud of desert sand and cactus needles.

Here, on the Mexican-American border, the journey to "El Norte" starts fresh every night for countless Latinos. Socks are pulled over shoes to avoid leaving footsteps in the sand. Garlic is tied around ankles to keep snakes and scorpions away. If everything goes well, the trip to Tucson takes four days to finish. Arivaca is the new portal for illegal immigrants to the United States. 

There are so many of them that they are running out of hiding places in the valley. "Imigrantes" huddle in every ditch and under every underpass. All the Border Patrol agents have to do to find illegal immigrants is follow the trail of garbage mounds, discarded ponchos and backpacks. There are toothbrushes and combs, too -- things the immigrants use to look respectable on the first day of their new life.

Last year alone, Border Patrol officers arrested 1.2 million people along this border. Half that number again may have entered the US without getting caught. Today the first prison van is quickly filled. The prisoners are ordered to remove their shoelaces and toss them into a plastic bin. They'll be back in Mexico before midday -- at least for now. "We'll see them again next week," one of the border patrol agents says. "No, tomorrow," grunts his colleague.

"Give me your tired, your poor..."

America is a nation of immigrants. "Give me your tired, your poor, your huddled masses yearning to breathe free," reads the inscription on New York's Statue of Liberty. But the nation is deeply divided over the question of whether this promise is valid for the tired and poor arriving every day in Arivaca Valley or elsewhere along the USA's 3,141 kilometer (1,952 mile) southern border.

Concern about the country's national identity -- and fear that terrorists may cross the border as easily as immigrants -- have made border security a hot-button topic. The Republicans are locked in a bitter debate over whether a generous program for foreign workers and amnesty are the solution to the problem, or whether closing the borders is the better option.

Samuel Huntington, author of the influential book "The Clash of Civilizations," argues in favor of closing borders. Hispanics don't want to integrate and are therefore at odds with the American dream, argues the cultural pessimist. He warns against a division of the US "into two cultures and two languages." It sounds almost as if "God's own country" were on the point of being invaded by an enemy. And the figures are indeed impressive. Not only do 11 million people live in the US illegally;the 41 million Hispanics living there, legally or not, are the nation's largest minority. Former Caucasian majorities in Miami and Los Angeles have become minorities; and in another ten years, the same will likely be true of New York and Washington. "Mexifornia" is the derisive nickname enemies of immigration have given to Latino strongholds such as California.

America's "Tower of Babel"?

Tom Tancredo, a House Republican who voted for a tougher immigration law last year, claims America is becoming a new "Tower of Babel."

The bill envisions sensors, drones, and giant fences along the southern border to prevent illegal transitions from the Third to the First World. Under this bill, anyone providing medical treatment to illegal immigrants would be legally punishable. The measure would "literally criminalize the good Samaritan and probably even Jesus," Democratic Senator Hillary Clinton has said.

In Aravaca, Reverend Randy Mayer has parked his red Mercury next to the prison van. "Los Samaritanos" reads the writing on the car doors. Members of Mayer's parish make their way to the desert five days a week, in order to help refugees. They speak of an "inhuman manhunt."

The US government has been extending border controls for years. In 1986, the Border Patrol's budget was raised by 1,000 percent. Fences surround parts of California, especially those close to the densely-populated regions of Mexico. Whoever wants to come north now has to make their way through the desert.

"Our government thought a place like this was a natural obstacle, and that no one would be so desperate as to try to make their way through here," Mayer says. "Now they're finding out that Latino refugees have no other choice." Mayer once found a baby carriage in the desert. Another time, a woman came stumbling towards him in high-heeled shoes.

Mayer leaves water bottles in the scorching sand and arranges for maps to be handed out on the Mexican side of the border. The maps tell refugees where the water bottles have been deposited. It's their only survival aid in the relentless heat. According to official statistics, 473 people died making the border crossing last year, a record number.

A man comes limping, his face contorted with pain, his arm resting on a giant pitchfork. He tripped over a rock in the darkness and injured his knees. He doesn't want medical help; he wants to return to Mexico. "He's lucky he can still walk," says Mayer, glancing at his watch. He needs to go to church; Bible class will begin soon. "All Washington is doing is putting these people in danger. But if they manage to get here, they're given a job."

The secret economy

This dilemma has led to a bizarre coalition of big business and churches. Many oppose the draconian border controls. A wall to ward off immigrants, all across the American continent? That would be like Berlin during the Cold War, says Tom Donohue, president of the US Chamber of Commerce. "We need these people," he adds. In fact, entire sectors of the US economy depend on the cheap labor that arrives from across the border. Illegal immigrants work in the giant slaughterhouses of the Midwest, they clean cars, wash dishes in restaurants and mow lawns in wealthy white suburbs.

America's booming economy loves Latinos. The workers don't belong to trade unions, they don't even get minimum wages, and employers don't have to pay for their health insurance, because they don't have any. The statistics indicate clearly enough that there is a kind of tacit agreement between the state and the refugees: In 2004, only three US businesses were persecuted for employing illegal immigrants.

Now the Senate has taken political action. Last week, the Judiciary Committee proposed a plan to grant conditional amnesty to illegal aliens. But it also attached conditions to the plan: Illegal immigrants would have to pay a $1,000 fine before they could qualify for amnesty and they would have to pay taxes. Illegal immigrants who have already been in the US for a number of years could also be given the option of guaranteed citizenship, a proposal that has drawn criticism from one of America's most-famous immigrants. "Granting citizenship to people who are here illegally is not just amnesty, it's anarchy," protested California Governor Arnold Schwarzenegger of the Republicans. Schwarzenegger has, however, backed plans for a temporary immigrant worker program.

President George W. Bush, who is facing considerable criticism from within his own party, wants to make concessions to both sides. He wants more border control and opposes the amnesty, but he's spoken out in favor of a temporary worker program. The president doesn't believe the border between a rich and a poor country can simply be sealed off. "Family values do not stop at the Rio Grande," Bush once said. "If you're a mother and father with hungry children, you are going to try to put food on the table. That's reality. That's called love."

Congressional elections will be held in November, and an overwhelming majority of Americans are demanding greater security along the US's southern border. But last week also saw Latinos asking for respect. "We have a dream too," hundreds of thousands chanted across the country. The two points of view seem irreconcilable -- so irreconcilable that it may be impossible to pass a new immigration law before the elections. Then things would stay the way they are in the Arivaca Valley. That's what Bruce Parks is afraid of.

Parks is a pathologist. He's chief coroner of Pima County, where Arivaca is located. Two Diesel generators hum in the courtyard outside his office, providing electricity for refrigerated trailers filled with corpses.

Heat stroke is a terrible death, the medic says. "Your body temperature rises up to 42 degrees Celsius (108 degrees Fahrenheit). People tear off their clothes. Then they look for a place to die." Last year, Parks was responsible for the autopsies of 191 people. Often dehydration has disfigured the bodies so badly that it becomes difficult to determine their gender.

Arizona's spring sun is still mild, but Parks is hoping that Washington will reach a decision quickly, because any day now the desert could turn into a lethal oven again.