By Caroline Hepker
Business reporter, BBC News, New Mexico
Despite the crackdowns, many Mexicans still want to go to the US
America's presidential race is picking up speed.
Both parties are preparing to officially crown their candidates and vice-presidential nominees.
But in the coming weeks the hopefuls will have to address head-on voters' greatest concerns.
Here in New Mexico, where Barack Obama and John McCain have campaigned in recent weeks, one of the most divisive issues is illegal immigration.
This is a so-called swing-state, one of those that could decide the election.
A sparsely populated, arid land on the US-Mexico border, New Mexico is a poor state.
Few job-seekers stay here and consequently the unemployment rate of just 3.9% is well below the national average.
It is here that employers must balance the need for a skilled and willing workforce against the severe penalties for hiring undocumented workers.
Businesses can be fined thousands of dollars and face jail sentences for knowingly hiring illegal workers.
'Pay you less'
In March, the Bush administration increased the financial penalties for the first time in almost a decade, whilst criminal prosecutions are on the rise.
Valentin crossed the border into the US illegally, and worked in construction for eight years, until he could get a legal work permit. He knows the dangers of that clandestine life.
"You need to find a job where they will take you on as you are," he says.
"Sometimes you have to tell the boss the truth. Sometimes that's good.
Illegal immigration is a big political issue in the US
"Other times they can take advantage of you and pay you less."
The young Mexican now works for Leslie Miller at a forge in Albuquerque, making steel construction beams.
Ms Miller, who took over the business from her father, admits to hiring undocumented workers despite the risks.
She says she pays them the same as local workers and argues that hiring the men is both the right thing to do, as well as, a necessity.
"We don't see a lot of Americans wanting to come and take these positions," she says.
"These people didn't take the jobs. They were jobs Americans didn't want to take."
Last year, there was a wave of demonstrations, debate and legal action in the US over illegal immigration.
In August 2007, the Washington-based Centre for Immigration Studies estimated there 12.5 million illegal migrants living in America.
The policy advocacy group wants to see fewer immigrants entering the US.
One year on, its survey shows an 11% drop in the number of illegal immigrants, to 11.2 million.
The Centre credits President Bush's clamp down. Economists says it is more likely the US economic slowdown that is deterring people.
Immigration lawyer John Lawit, who represents Valentin in Albuquerque, says the government's tough agenda is a mistake.
"The concept of making employers into policemen and putting a wedge between employers and employees is nonsense," he says.
"The employer wants to protect the workforce, the Department of Homeland Security wants to deport the workforce."
Caught in the middle, employers such as Leslie Miller worry about being caught on the wrong side of the law.
"It is very expensive if they came down and cited us for having [undocumented] employees. It's jail terms," she says.
"The financial risk is enormous. Until we decide it's important to educate our children and give them vocational skills, these people are the only ones that are coming able to do this work."
Be they Republican or Democrat, this is a dilemma that will doubtless land on the desk of the next US president.