THURSDAY was a sad day at the U.S. District Court in Alexandria. Judge James Cacheris took pleas in two cases that are a dismal reminder of how far the drug epidemic has spread. In both, men who were in positions of trust and supposedly dedicated to upholding the law admitted to involvement in drug schemes.

Gerald Robbins, a criminal defense attorney who was once a federal prosecutor in the U.S. Attorney's Office in the District, pleaded guilty to participating in a drug transaction involving more than a quarter of a million dollars worth of cocaine. He admitted that he arranged to store eight kilograms of the drug for his client's wife with the understanding that he would be paid $10,000 and be given a loan of another $20,000. Now he faces not only a possible four years in prison but disbarment. What could a lawyer, an officer of the court, have been thinking of when he involved himself in such a risky scheme?

On the same day, Judge Cacheris also heard two guards at the Lorton prison complex admit that they had taken bribes in order to supply drugs to inmates. Marlon Epps and Rigoberto Godoy detailed arrangements they had made to smuggle contraband into Lorton. These revelations, coming on top of Post reporter Leon Dash's recent series on drug use by D.C. Jail guards, point to continuing serious problems in the D.C. Department of Corrections. How can the inmate population be supervised, let alone rehabilitated, if those responsible for their care are themselves using drugs or contributing to continued addiction among prisoners?

These Alexandria cases come in a week when the mayor of Washington was convicted of drug possession, and a former special assistant to Attorney General Dick Thornburgh was indicted for cocaine possession, making false statements and conspiracy. On Friday, these charges were brought in Harrisburg against Henry Barr, whose duties in the Justice Department included overseeing criminal investigations across the country. All these cases illustrate that involvement with drugs is not a problem limited to whites or blacks, rich or poor. When men with positions of trust within the criminal justice system cannot be counted upon to abide by the law, it is clear that the drug problem permeates every social and economic level and threatens to corrupt the administration of justice. Prosecutions like these are, and should be, a top priority if public confidence in law and order is to be maintained.