In Nuevo Laredo, reports The Dallas Morning News, the Zeta cartel has become a state within a state:

The "police" for the Zetas paramilitary cartel are so numerous here - upward of 3,000, according to one estimate - that they far outnumber the official force, and their appearance further sets them apart.

Most are teens sporting crew cuts, gold chains and earrings, with shorts worn well below the waist and cellphones pressed to their ears. These "spotters" seem to be everywhere, including elementary schools, keeping tabs on everything and everyone for the area's most dominant drug cartel....

The omnipresent cartel spotters are one aspect of what experts describe as the emergence of virtual parallel governments in places like Nuevo Laredo and Ciudad Juarez - criminal groups that levy taxes, gather intelligence, muzzle the media, run businesses and impose a version of order that serves their criminal goals.

"President (Felipe) Calderon's war on drug cartels has been such an abysmal failure that entire regions of Mexico are effectively controlled by non-state actors, i.e., multipurpose criminal organizations," said Howard Campbell, an anthropologist and expert on drug cartels at the University of Texas at El Paso.

"These criminal groups have morphed from being strictly drug cartels into a kind of alternative society and economy," Campbell said. "They are the dominant forces of coercion, tax the population, steal from or control utilities such as gasoline, sell their own products and are the ultimate decision-makers in the territories they control."

As the Zetas impose taxes, they also produce tax exiles:

A Mexican dentist said he tired of paying a weekly extortion fee of 800 pesos, about $70, in Juarez, and, after suffering a beating for nonpayment that almost killed him, he made the move to El Paso.

He now runs a clandestine clinic in his El Paso home, using his car to pick up patients at a distant location and discreetly driving them into his garage, where he welcomes them to his office.

"Whether you agree, or disagree with this war, one thing is clear. This will go on for years," the dentist said. "This clandestine office is Plan B for now."

Elsewhere in Reason: Brian Doherty interviews Howard Campbell.