Four years and 50,000 troops into President Felipe Calderon's drug war, the fighting has exposed severe limitations in the Mexican army's ability to wage unconventional warfare, tarnished its proud reputation and left the U.S. pointedly criticizing the force as "virtually blind" on the ground, the Los Angeles Times reports.

The army's shortcomings have complicated the government's struggle against the narcotics cartels, as the deadliest year of the war by far comes to a close.

Though long employed to destroy marijuana and poppy fields in the countryside, the army hadn't been trained for the type of operations needed to fight groups trafficking cocaine through border cities.

"The army has never worked in urban operations against drug trafficking, in urban cells," said Raul Benitez, a national security specialist at the National Autonomous University of Mexico. "It's the first time it is engaged in urban warfare. It has to learn."

Instead, the army often relies on numerical superiority over intelligence and has frequently fallen back on time-worn tactics, such as highway checkpoints, that are of limited use against drug traffickers, especially in cities.

Checkpoints have also been the scene of serious human rights violations, including deadly shootings of civilians. Allegations of abuse at the hands of the army, one of the most respected institutions in the country, have soared. Mexico's human rights commission this year received nearly double the number of complaints it had gotten in the previous three years combined.

Read the entire story at latimes.com