Helmeted army troops steer Humvees past strip malls in the border city of Nuevo Laredo, some of the 40,000 soldiers and 5,000 federal police officers President Felipe Calderon has deployed to secure large swaths of the country against entrenched drug traffickers.
Criminals unleash machine guns and grenades in urban battles that the State Department describes as "equivalent to military small-unit combat."
In the year and a half since Calderon launched a crackdown against drug gangs, about 4,100 people have died, the government says. At least 1,400 have been killed so far this year, including 170 in Tijuana, about 400 in Ciudad Juarez and 270 more in the western state of Sinaloa.
Many of the dead were gang members killed by rivals or by the government. Others have been bystanders. But at least 450 police officers and soldiers also have been killed.
"It is a real fight," Calderon told reporters recently. "It is a war."
The president asserts that the level of violence is one measure of success. He says the cartels have been hurt badly, and that they are now lashing out at the government and battling one another for control of territory.
In addition to using military force, Calderon is seeking to strengthen and clean up Mexico's police. Judicial reforms, such as expanded use of plea-bargaining, are aimed at inducing low-ranking suspects to testify against their superiors. And Calderon has agreed to extradite more than 70 jailed drug suspects to the United States.
But for now, the bulwark of his strategy is the army, which says it has made more than 5,800 arrests and intercepted 2,900 tons of marijuana and 24 tons of cocaine. One commentator calculated that overall, drug seizures have cost traffickers as much as $20 billion. The U.S. Drug Enforcement Administration reported in November that street prices of cocaine and methamphetamine had risen, and purity levels had fallen signs interdiction was working.
Despite the effort, many doubt that Calderon is winning the war. A poll in the Reforma daily on Sunday said 53% of Mexicans believe drug gangs have the upper hand. The killing of Mexico's top drug cop in his Mexico City home last month by traffickers with keys to the house shows infiltration at the highest level, they note.
In Sinaloa state, traffickers have hung posters mocking the 3,600 troops there as "little lead soldiers." In Nuevo Laredo and Reynosa, another border city, recent banners advertised jobs in the Zetas, one of the country's most feared crime groups, to soldiers and former soldiers. They offered "good wages, food and help for your family."
Drug traffickers use severed heads as a tool of terror, leaving them with notes to taunt police and one another.
Political analysts say the campaign has succeeded mainly in pushing violence from one region to another, without uprooting the mafias that are challenging the power of the Mexican state. Federal troops often are introduced only after particularly violent outbreaks. They have helped bring calm to Nuevo Laredo, in Tamaulipas state, for example, only to see the killing increase in Baja California and Chihuahua, or farther south in Guerrero state.
"It's a strategy of temporary occupation that achieves just moments of relative quiet, only to return to worsening violence," said Eduardo Valle, a writer and commentator who once worked as an advisor in the federal attorney general's office.
Many also doubt the Mexican government can do much more as long as demand in the United States remains high.
Calderon is relying too heavily on the military and ignoring other fronts such as money laundering, arms trafficking and intelligence gathering, said newspaper columnist Jorge Zepeda Patterson. In fact, drug traffickers often have better intelligence from corrupt police than the army has.
Mexico has long had problems with the drug trade. What's new is the scale and ferocity of the violence. Atty. Gen. Eduardo Medina Mora says deaths are up 47% this year compared with last year.
Largely concentrated along Mexico's 2,000-mile border with the United States and the Gulf of California state Sinaloa, the violence stems from the government crackdown, clashes between the cartels and internal fighting within the crime groups.