The phone calls to Claude Arnold's office tell him the debate over illegal immigration is heating up.

Arnold, who oversees Immigration and Customs Enforcement operations for most of Southern California — including Orange County — says immigration activists have been calling him more often lately.

Some criticize one of the department's missions — cracking down on illegal immigration.

Others accuse the department of being too lax.

"They say we're not doing enough and should be arresting every illegal alien in the country," Arnold said, a number estimated at 12 million or more.

Still, the 44-year-old tries not to get caught up in the cacophony of arguments, he said, and instead focuses on his task — dismantling the infrastructure that perpetuates human and drug smuggling operations along the U.S. and Mexico border.

Arnold spoke from his Long Beach office – about 90 miles from the Mexican border -- about the region's significance in the fight against illegal immigration and the crime surrounding the smuggling operations.

The Los Angeles metropolitan area is ground zero for illicit trafficking of humans, drugs, money, weapons, contraband and counterfeit goods, Arnold explained. The region he watches over has the second largest city in the nation, the largest sea port in the Northern Hemisphere and is close to the Mexican border.

"It's good for business and good for illegitimate business," he said.

Arnold, who leads arguably the most important region in the fight against illegal immigration, says he found his law enforcement calling at the age of 4.

As a youngster, he jumped on his bike to go looking for his siblings at the local school and was unaware that he'd been gone for hours. Worried, his mother called the police, who eventually found him at the school and asked him to get in the squad vehicle. Reluctant to follow the commands of a stranger, even one in uniform, Arnold refused to get in the car and instead rode his bicycle home.

"The police officer rode beside me three blocks. It took a half hour... just to make sure I was safe," Arnold said and laughed.

While his early, positive exposure to law enforcement sparked his interest in the field, the Midwest native said his cultural background makes him understand some of the immigrant spirit.

Arnold, who is fluent in Spanish and French, said his grandfather legally immigrated to this country from France. He said he understands some of the immigrant experience after growing up listening to stories about how his grandfather spoke no English when he first arrived in the early 1900s.

"He was a dishwasher," Arnold said. "He hated that job."

His grandfather would later become an engineer at Western Electric, keeping his job while others lost theirs during the depths of the Great Depression.

While he understands the desire of those who come here for a better opportunity, he said it's paramount that people come and stay legally instead of perpetuating the illegal activity that's inherent to human smuggling. It has increasingly become intertwined with drug trafficking operations, Arnold added.

ICE is in charge of investigating any violation of federal law when something or someone crosses the border — virtually or physically, Arnold said. That's why, he said, the area he oversees is so important.

The Los Angeles area is essentially a consolidation point for drug smugglers, Arnold said. It's where drug trafficking rings combine their proceeds from all sales across the country and repackage the cash into smaller loads to send across the border.

Arnold said his agency has a strategic approach to the complex problem of illegal immigration. The region has a large, diverse community that's a staging area for those smuggled into the country — many looking for jobs.

That's why, he said, ICE is ramping up efforts to go after employers who hire workers who are in the country illegally.

To do that, the agency has refocused its worksite enforcement efforts, Arnold said. It's important to cut off the job supply for those in the country illegally — a major reason most come in the first place, he said.

"For those who think we should go out and arrest every illegal alien we see? That wouldn't be the most effective use of resources," he said.

The father of two joined the agency when it was Immigration and Naturalization Services. He had national oversight over ICE investigations on transnational gangs, developing and deploying a national gang initiative in 2005 called Operation Community Shield. The initiative is tasked with dismantling gang operations and targeting gang members who are in the country illegally.

Arnold, who developed relationships with informants for five years as an undercover agent, said neighbors within the immigrant community would break out in applause when agents arrested a gangster who'd long terrorized the community.

"Their lack of value for human life is astonishing," Arnold said of the drug smugglers and gang members. "You wonder how they get that way. Their perception of life is so skewed and different than anyone else."

While the agency goes after those in the country illegally, he acknowledged that these people can also become victims.

"A lot of people who come here illegally are victimized by the smugglers, by employers who are looking to employ someone for less than competitive wages," Arnold said.

Those in the country illegally can also play the part of perpetrators, he added. Some join the drug and human smuggling rings or become gang members.

"Really what we do is focus on those people -- the real bad guys," Arnold said.