Kerlikowske's reputation for innovative approaches to law enforcement and McLellan's stature as a treatment scientist make them "a perfect match," Pasierb said.
Although hardly known, even locally, outside his field, McLellan is regarded as a leading researcher on a range of addiction-related issues.
As a scientist at the Veterans Administration Medical Center in Philadelphia in the 1980s, he led development of two measures, known as the addiction severity index and treatment services review, that characterized multiple dimensions of substance abuse. The tools, used worldwide, help determine the type and duration of treatment.
In 2000, he was lead author of a groundbreaking paper that compared drug addition with chronic medical conditions.
When diabetes or asthma patients relapsed after treatment ends, he argued, doctors concluded that intervention worked and that treatment needed to be continual.
"In contrast, relapse to drug or alcohol use following discharge from addiction treatment has been considered evidence of treatment failure," the authors wrote in the Journal of the American Medical Association.
McLellan, 59, grew up outside Harrisburg and did his graduate work at Bryn Mawr College, earning a doctorate in 1976. In 1992 he cofounded the nonprofit Treatment Research Institute to study and adapt promising scientific findings into clinical practice and public policy.
He worked with the State of Delaware, for example, to implement a system that tied part of the payments to state-funded treatment centers to predetermined measures for success.
"I think his long and rigorous examination of how drug-abuse treatment is delivered is pretty unique," said David Friedman, director of addiction studies at the Wake Forest University medical school.
People in the field have long been frustrated by drug policies under both Democrats and Republicans that they say were driven not by science but by ideology - essentially, arrest the drug suppliers and get the users out of sight.
Friedman was buoyed several weeks ago when Secretary of State Hillary Rodham Clinton made an unusual acknowledgment of the role played by domestic consumers of illicit substances.
"Our insatiable demand for illegal drugs fuels the drug trade," she said in Mexico.
Friedman said that "if that's the way the administration feels about this, then all of a sudden the deputy for demand reduction" - McLellan's job, in addition to being the second in command - "becomes a very important position."
Success will depend at least as much on McLellan's relations with Congress as it will on his scientific background.
"I'm hoping that what happens is, Tom is able to build a groundswell," said Roland Lamb, director of Philadelphia's Office of Addiction Services. The result would be a national conversation on addiction and treatment.
A. Thomas McLellan
Experience: Adjunct professor of psychology in the department of psychiatry, University of Pennsylvania School of Medicine; cofounder and chief executive of Treatment Research Institute in Philadelphia.
Education: B.A., Colgate University; M.S. and Ph.D., Bryn Mawr College; postgraduate training in psychology at Oxford University.
Personal: Born May 29, 1949, in Staten Island, N.Y., and raised in Mechanicsburg, Pa.; he and his wife, Deni Carise, have one grown son and live in the Bella Vista section of Philadelphia.
Contact staff writer Don Sapatkin at 215-854-2617 or email@example.com.