While Cuban inmates held prison guards and the nation's attention hostage last November, drug smugglers took advantage of a convenient distraction, courtesy of Attorney General Edwin Meese III.

Some 300 officers of the U.S. Border Patrol, who usually guard the Mexican border were pulled from their posts by Meese to bolster security at the federal prisons in Oakdale, La., and Atlanta, in the wake of the riots.

Relocating the troops for 10 days "virtually left the border wide open," said Rep. Glenn English (D-Okla.) at a recent congressional hearing. The unpublicized meeting was attended only by English, his staffer and a few witnesses.

Asked if drug traffickers knew about the weakened border patrol, Alan Eliason, a senior U.S.-Mexican border official, replied, "I have no doubt whatsoever that the smugglers knew that we had a depleted work force."

There is no handy statistic to pinpoint the extra trunkloads of cocaine and marijuana that may have slipped across the border unnoticed during the prison riots. But the lapse in security may just be the latest bungle in the Reagan administration's war on drugs -- a war with a record of wins that makes it the domestic equivalent of Vietnam.

The hearing, held by the subcommittee on government information, justice and agriculture, revealed that drug dealers were more aware of the weakened border surveillance than was the official in charge of it, Francis A. Keating II, assistant secretary of the Treasury for enforcement.

Keating conceded he was the "acting chairman {of a task force} of all enforcement agencies," but he conceded he was not notified of Meese's decision to shift some of the border forces to the prisons. Keating said he was in no position to question the wisdom of the attorney general.

English bristled at that: "The point is . . . war has been declared, supposedly a war on drugs, and I think that this raises questions about the seriousness of the effort."

In August 1986, Meese and Vice President Bush announced the advent of Operation Alliance, a drug-enforcement network assembled to curb smuggling across the border. The operation has been heralded by the administration as one of the cornerstones of its drug-enforcement effort. But the subcommittee, chaired by English, asserts that Operation Alliance has not lived up to its billing.

Administration claims of success do not stand up against a recent General Accounting Office investigation, which showed that the number of cocaine seizures along the border was down by more than 50 percent in the first year of Operation Alliance.

Our associate Jim Lynch has learned that the officers who left the border for the prisons were members of a little-known SWAT team called BORTAC -- Border Patrol Tactical Unit. They stood on the outskirts of the prisons waiting for a command to storm the facilities. That command never came.

A spokesman for Meese said the attorney general decided that the prison riots were "a high-priority occurrence" and that Meese was aware of the impact on the border patrols.