THE BURNED OVER DISTRICT

Time and again we have seen the results of US abandonment of those who have helped it during the wars we have lost, including Viet Nam, Iraq and Afghanistan. The New York Times takes a look at what has happened to one man who helped the US in its longest running losing war effort, The War On Drugs.

Mr. López played a leading role in what is widely considered the biggest drug-trafficking case in Mexican history. The episode — which inspired the 2000 movie “Traffic” — pitted the Mexican military against the United States Drug Enforcement Administration. Throughout the 1990s, Mr. López worked closely with them both. He served as a senior adviser to the powerful general who was appointed Mexico’s drug czar. And he was an informant for the D.E.A.

His two worlds collided spectacularly in 1997, when Mexico arrested the general, Jesús Gutiérrez Rebollo, on charges of collaborating with drug traffickers. As Washington tried to make sense of the charges, both governments went looking for Mr. López. Mexico considered him a suspect in the case; the D.E.A. saw him as a potential gold mine of information.

The United States found him first. The D.E.A. secretly helped Mr. López and his family escape across the border in exchange for his cooperation with its investigation.

Dozens of hours of testimony from Mr. López about links between the military and drug cartels proved to be explosive, setting off a dizzying chain reaction in which Mexico asked the United States for help capturing Mr. López, Washington denied any knowledge of his whereabouts and the D.E.A. abruptly severed its ties with him.

The reserved, unpretentious husband and father of three has been a fugitive ever since, on the run from his native country and abandoned by his adopted home. For more than a decade, he has carried information about the inner workings of the drug war that both governments carefully kept secret.

The United States continues to feign ignorance about his whereabouts when pressed by Mexican officials, who still ask for assistance to find him, a federal law enforcement official said.

It is a twisted tale of valuable assistance and worthless thanks as only the US can provide.