In Arizona, the cartels grossed an estimated $2 billion last year on smuggling humans, Goddard said.
In recent years, the U.S. government has taken significant steps to go after illegal immigrant smugglers on a global scale, setting up task forces, launching public awareness campaigns and creating a Human Smuggling and Trafficking Center to fuse intelligence from various agencies.
But at the southern border, the effort has stumbled, in part because Homeland Security and various Justice Department agencies have overlapping responsibilities and are engaging in turf battles to keep them, Goddard and numerous other federal and state officials said.
The vast majority of ICE agents cannot make drug arrests, for instance, even though the same smugglers are often moving illegal immigrants.
The reason: The Drug Enforcement Administration has not authorized the required "cross-designation" authority for them, according to Kibble and others. A top DEA official said that was partly to prevent ICE agents from unwittingly compromising ongoing DEA drug investigations and informants working the cartels.
Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives focus almost exclusively on cartel efforts to smuggle large quantities of American-made weapons into Mexico.
"The only way we're going to be successful is to truly mount a comprehensive attack upon the cartels. They're doing a comprehensive attack on us through all four of these different criminal activities," Goddard told a Senate Judiciary subcommittee.
"I'm afraid in this country we tend to segregate by specialty the various areas that we are going to prosecute. And our experience on the border is we can't do that. We've got to cross the jurisdictional lines or we're going to fail."
Kibble agreed, saying that the cartels' diversification will require federal agencies to work together. "It means we need more teamwork so things don't slip through the cracks."
He added: "We are very focused on it and applying law enforcement pressure to all aspects of the cartels' activities."
Asked for comment, Justice Department officials referred calls to Homeland Security.
But authorities are also hampered by budget shortcomings and other obstacles.
Even though ICE has primary responsibility over illegal immigrant smuggling, it has only 100 agents dedicated to the task, Kibble said.
There is no line item in ICE's budget for human smuggling, so no one knows how much money is being spent on it, he told Sanchez's border subcommittee, before acknowledging that the agency needs more resources to fight the problem.
There are also not enough resources for providing medical treatment and protection for those illegal immigrants who are caught, so many of them are not available to testify, said Anastasia Brown, the director of refugee programs for the U.S. Conference of Catholic Bishops.
As a result, there have been relatively few prosecutions and convictions.
In fiscal 2008, ICE initiated 432 human smuggling investigations, including 262 cases of alleged sexual exploitation and 170 cases of suspected labor exploitation.
Those efforts resulted in 189 arrests, 126 indictments and 126 convictions related to human smuggling, according to Homeland Security documents provided to Congress.
Cameron H. Holmes, an assistant Arizona attorney general at the front lines of the fight against cross-border human smuggling, agreed that federal authorities were trying to collaborate better.
"Are they working together enough? Absolutely not. Are they being successful? Look around," Holmes said, before describing details of illegal immigrant smuggling cases in which people were killed or enslaved for years.
"We have a multibillion criminal industry that has grown up in the last 10 years and it all involves violations of federal law. I would not call that a success."