In the latest confrontation over federal antidrug guidelines for college campuses, national drug control policy director Bob Martinez has warned Stanford University that it risks losing all federal aid because of the activities of a senior lecturer who has openly boasted that he carries illegal drugs to campus in his backpack.

After receiving a letter from Martinez, Stanford President Donald Kennedy announced Friday night that the School of Engineering had placed Stuart Reges, an award-winning computer science lecturer there for 11 years, on paid administrative leave.

Kennedy said the school would investigate Reges's claims that he intentionally violated the school's drug and alcohol policy and once counseled a student to "experiment" with Reges's "drug of choice," a hallucinogen called MDA.

"I am somewhat stunned," said Reges, 32, in a telephone interview yesterday. "If the university is going to fire people who advocate drug use, it's ludicrous, the war on drugs has gone much too far. . . . This is a free-speech issue. It seems that university staffers are not allowed to express an opinion. It's a tremendous threat to intellectual freedom."

But Bush administration officials expressed concerns about the adequacy of Stanford's response, noting that although Reges openly boasted of his drug use in articles in the Stanford Daily last November, the school had taken no action.

"My impression is that this hasn't exactly been a secret at Stanford. This guy has been shouting about his involvement with drugs for six months or more," said an aide to Martinez. "It's too bad that it takes a half-year and a letter from a White House official to remind university administrators of their legal responsibilities."

In his April 12 letter, Martinez warned the Stanford president that "to retain eligibility for federal funding and financial assistance," colleges must adopt antidrug policies that include "sanctions on students and employees for violations."

"In all candor, I would find it beyond comprehension that a man who openly professes to have encouraged an undergraduate to ingest MDA could continue to enjoy faculty privileges at a pace-setting institution like Stanford University," wrote Martinez.

Aides to Martinez said last week that they had sent copies of a letter they received from Reges to the Justice Department for possible criminal prosecution. In that and other letters, Reges has baited federal and college officials, calling himself a "responsible drug user."

"I am doing everything I can to make fools of you," wrote Reges. "I still carry illegal drugs in my backpack while on campus in direct violation of Stanford's policy. . . . I do not fear any of you, I have not changed my behavior, and nothing bad has happened to me."

Reges said that he never encouraged a student to use MDA, he simply advised the student that his concerns it was addictive or would cause him to "lose control" were unjustified. MDA is an amphetamine derivative, usually taken in capsule form, that produces euphoric effects.

"About the most dangerous thing you might do under the influence of MDA that you wouldn't do otherwise would be to hug or kiss someone," he wrote in the Nov. 8 Stanford Daily.

Reges said in an interview that he sent a copy of his letter to Martinez to a Stanford vice president, and when he received no reply, sent her two electronic mail messages seeking confirmation that she had seen it. "I think they have been hoping all along that they won't have to enforce" the antidrug policy, he said.

The Stanford incident comes amid a growing national debate over drug policies on college campuses prompted by the March 21 drug raid at University of Virginia in which three fraternity houses were confiscated. The raid and the adoption in October of federally imposed antidrug policies on campuses have been questioned by some critics who note that recent federal surveys have reported that illegal drug use among college students has dropped to its lowest level in more than a decade.

Martinez last week said the Bush administration intends to closely monitor the actions of university administrators on the matter. Adopting an antidrug program "means more than simply posting a bulletin in a student union," he said. "We're going to be looking for evidence of just how effective they are."

But Reges said it was the government's effort to involve universities in enforcing drug laws that he found most objectionable. "I don't think the university should care what I carry in my backpack," he said.

Reges said his introductory courses in computer science were rated by students as among the most popular at the School of Engineering and that six years ago he won a university award for undergraduate education.