Mexico is at war.
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.
The No. 2 police officer from Ciudad Juarez dies in a hail of bullets, and his boss resigns after receiving threats over the police force's own radio frequency.
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.
Calderon's predecessor, Vicente Fox, also sent troops into the streets, but his more limited effort was widely regarded as ineffective. Nearly 9,000 people were killed in drug-related violence during Fox's six-year term. Calderon, politically weak after winning a disputed election, chose a popular issue by taking a tougher approach to drug traffickers.
Troops are now patrolling in 18 of Mexico's 31 states. Working alongside federal police, they carry out raids and set up checkpoints to search for drugs, weapons and traffickers. They have disarmed municipal police to check whether their weapons have been used in shootings, tested officers for drug use and investigated them for criminal ties.
Army generals are de facto police chiefs in some zones along the border.
U.S. officials have praised Calderon's decision to extradite drug suspects, including Osiel Cardenas, the former leader of the so-called Gulf cartel, despite Mexico's traditional reluctance to send citizens to the U.S. to face charges. The Bush administration also has proposed a $1.4-billion three-year aid package for Mexico and Central America that would provide Mexico with helicopters, high-tech scanners and other equipment.
Most drug experts agree that the army has made it harder to move drugs to U.S. markets and sharpened gang turf battles. But there is no sign that it has dislodged trafficking groups from their strongholds, or that cartel infighting will come to an end any time soon.
Even in places such as the western state of Michoacan, where large numbers of troops were sent, suspected drug hit men fatally shot Mayor Marcelo Ibarra of Villa Madero on Sunday as he was returning from a family outing, the state attorney general's office said.
In Nuevo Laredo, where drug gangs once battled openly in the streets, officials and residents say the presence of hundreds of troops has created an air of relative calm.
"It's a lot safer," said Juan Pablo Castano Garza, an investment broker. "It used to be that people were afraid to go out at night."
But residents still drop their voices to a whisper when talking about the Zetas, whose original leaders were former soldiers. The Zetas have cemented the dominance of the Gulf cartel in Nuevo Laredo.
In Sinaloa state, the government faced a new setback last week. Grenade-hurling hit men killed seven federal agents and wounded four others in Culiacan, the state capital.
Organized crime has nationwide reach, with drug trafficking groups vying for control of shipment routes. But each works from a home base, with the Gulf cartel in Tamaulipas and the three other major gangs operating from Ciudad Juarez, Sinaloa state and Tijuana.
Analysts and officials say factional fighting is the result of unusual ferment in recent years due to the emergence of spinoff groups and the arrests or deaths of older crime bosses capable of brokering peace.
The archetypal Mexican drug cartel, with a kingpin leader and a top-down hierarchy, appears to be giving way. In place of a handful of cartels that have dominated drug smuggling in Mexico during the last three decades may emerge a multitude of smaller groups seeking a piece of the action.
The alliance of traffickers in Sinaloa is showing signs of coming apart as a result of fighting between Joaquin "Shorty" Guzman and a former deputy, Arturo Beltran Leyva.
This already has happened to the Tijuana-based Arellano Felix organization. The death of Ramon Arellano Felix in a 2002 shootout with police in Mazatlan, and subsequent arrests of brothers Benjamin and Francisco Javier, has left day-to-day operations in the hands of less-established subordinates, who are themselves under pressure. Federal police in March arrested Gustavo Rivera Martinez, the gang's suspected financial mastermind, and Saul Montes de Oca, a reputed cell leader.
Remnants have branched into enterprises such as kidnapping and car robbery. Internal tensions within the Arellano Felix group erupted April 26, when gunmen battled along a commercial street in the middle of the night. The shootout left 13 gunmen dead, and littered the street with 1,500 spent casings and nearly two dozen damaged vehicles.
The Tijuana gunfight apparently pitted factions led by two lieutenants, Teodoro Garcia Simental and Jorge Briceno.
The introduction of 3,300 federal troops, including reinforcements sent after the April 26 shootout, has added a new element. Soldiers have engaged in several shootouts with drug suspects, including a three-hour battle near an elementary school in broad daylight.
"The violence we are seeing in Tijuana is part of the restructuring of the cartels. The process of fragmentation is just beginning," said Jorge Chabat, a Mexico City-based security analyst.
In Ciudad Juarez, violence has surged since the beginning of the year. More than 100 people died in March, prompting Calderon to send an additional 1,500 soldiers to augment the 500 already there. The slayings slowed but then picked up.
Last month, the city's No. 2 police officer, Juan Antonio Roman Garcia, died in a torrent of bullets outside his home. A week later, his boss, Police Chief Guillermo Prieto Quintana, quit after receiving threats by telephone and over the police force's own radio frequency.
A retired military official, Roberto Orduna Cruz, has been named to succeed him.
Officials say police will get heavier weaponry, including compact machine guns and more powerful handguns.
"We are going to win, although it might not look like it," said Medina Mora, the attorney general.