When the US State Department's new anti-human trafficking chief took his position in June, he found himself tasked with bringing nearly 50 countries in line with US standards for fighting the practice.

Cambodia is one of those countries, and its efforts have not been strong enough, Ambassador Mark Lagon, head of the anti-trafficking office, said in a recent interview.

"Over time we've tried to get Cambodia's attention. At one point in the past it was subject to partial sanctions," Lagon said.

Cambodia remains on a US watch list for countries that are not doing enough to fight the movement of people for sex or labor. This is the second year it has been on the list, and, Lagon said, it can't stay there forever. It must either improve, or fall back onto a list of countries subject to US sanctions for their complicity in the practice.

The US estimates about 800,000 people are trafficked between nations each year. Most of them are women, and nearly half of them are under 18 years old. In Asia, Lagon said, that means Burmese victimized in the Thai fishing industry, sex trafficking to Malaysia, and high numbers of people shipped across China for labor in brick kilns and on farms.

In Cambodia, most of those trafficked are sex workers.

"At a certain point, one has to ask the question, is this a matter of will, rather than a matter of lacking capacity?" Lagon said.

Cambodia has not done enough to stop corrupt officials—including the national police—that allow the slave trade to thrive.

The worst of that is child prostitution, with customers from Asia and abroad.

"Americans as tourists can be insidious consumers of sexually exploited children," Lagon said, "and we're going to do everything we can, in partnership, to fight those bastards."

The practice is difficult to destroy at its roots. Traffickers are devious. They prey on the hopes of the rural poor, promising them a better life. They often find a ready ear.

"They say, 'Migrate to this other place, other part of the country, another neighboring state [country], there will be better economic conditions there," Lagon said. "And they often describe a different life, a life as a dancer, a life as a domestic servant, and it turns out to be something frightfully different."

Recruiters will ask to hold a passport, an obvious warning sign and an easy way for criminals to control trafficking victims. And human trafficking is lucrative, making it difficult to stamp out.

In Cambodia, police officials, including National Police Chief Hok Lundy, have been implicated in the crime of buying and selling human beings for the sex trade.

Although some US agencies work with Hok Lundy, and he has denied involvement, Lagon, who's former boss was a strong opponent of the police chief, said he has not seen satisfactory proof from Hok Lundy to clear him of the allegations.

"The burden of proof must always lie with officials who have been corrupt and who have been part of the problem and part of dehumanization of their fellow citizens," Lagon said. "That will always be the case with Hok Lundy."

Until recently, the US State Department refused to allow Hok Lundy in the country , and Lagon said such measures may be working.

Agencies like the Federal Bureau of Investigation now work with the police, but Lagon said the US is still pushing the authorities to clean up.

"We're trying to work, region-wide, on the key to the puzzle," he said. "And the key to the puzzle is rule of law."

Without the rule of law, he said, there never be dignity for all.