By Elizabeth Valk Long

You won't find TIME correspondent Elaine Shannon covering the ever changing, ever dangerous international narcotics trade from the safety of her Washington office. For this week's story on the growing influence and sophistication of Mexican cartels, Shannon traveled to one of the front lines of the war on drugs: the U.S.-Mexico border town of El Paso, Texas, which has become a prime gateway for drug smugglers. Thanks to an alliance between the Cali cartel of Colombia and alleged Mexican drug lord Amado Carillo Fuentes, Shannon says, "60% of the cocaine shipped to the U.S. now passes through Mexico. In this case, two plus two equals 10."

"Elaine is tough and careful and fair," says Dan Goodgame, chief of our Washington bureau. "Her beat is law enforcement, and it's one of the most challenging because federal agents are notoriously difficult to get close to. Several have told me they admire Elaine because she works the way they do. She does her homework before the interview and then gets right to the point."

It also helps that she's funny and exuberant, salting her conversation with north Georgia expressions that cannot be published in a family magazine. Shannon does some of her best work in biker bars and other places where she can meet her sources-from both sides of the law -- without their being spotted.

But her low profile is proving difficult to maintain. When Shannon showed up at a U.S. Drug Enforcement Agency post while working on the cartels story, agents asked her to autograph copies of her book Desperados: Latin Drug Lords, U.S. Lawmen, and the War America Can't Win. Her good relations with law-enforcement officials, however, do not keep her from asking tough questions-as she did in her award-winning coverage of how U.S. government agents mishandled the Waco, Texas, siege two years ago.

"Elaine is an incredibly determined journalist who uncovers a lot of information well below the surface," says senior editor Jim Collins, who edited the cartels story. Which is why Shannon was also part of our team in Phoenix, Arizona, last week covering the annual meeting of the National Rifle Association. "Traditionally, members of the n.r.a. have been big supporters of law enforcement," she notes. "But over the past eight to 10 years, n.r.a. leaders have espoused an increasingly radical, antigovernment view." That kind of complex and puzzling situation is perfect for Shannon's get-to-the-bottom-of-it style.