AS VETERANS and almost everyone else know, a "general" or "undesirable" discharge from the armed forces carries with it a permanent stigma. So it has been grossly unfair, not to mention pigheaded, for the Army to resist so long the upgrading of the less-than-honorable discharges it gave illegally to about 10,000 Vietnam-era soldiers. Now that Judge Barrington D. Parker has ordered the records to be changed, the Army should get on with the job.

The men were thrown out of the service as drug abusers after having been compelled to incrominate themselves by taking urinalysis tests. The testing program had been introduced in 1971 as a way to steer drug users into counseling sessions, but it quickly became a device for directing them out ot the Army. It was used that way until the Court of Military Appeals ruled, four years ago, that the test results could not be made a part of proceedings against them because the tests were compulsory and the soldiers had not been warned of what might happen if they submitted.

The Army, while stopping the practice immediately, saw no need to repair the damage it had done to 10,000 veterans. It argued that changing the records would be difficult, costly and unfair to those who had earned honorable discharges. Besides, it reasoned, some of those 10,000 would have been discharged dishonorably even if the test results had not been used (try to follow that logic).

The numbers suggest a different story. Of the 7,386 servicemen discharged for drug abuse in 1972, 1973 and 1974, a total of 6,762 received less-than-honorable discharges. Of the 5,525 discharged for the same reason in 15 months during 1976 and 1977, only 25 received less-than-honorable discharges. That means a soldier's entire future was jeopardized if he was caught by the Army as a drug user in the early 1970s but was not at all if he was caught in the late 1970s. This kind of unequal, and unfair, treatment, especially when it is the product of illegal conduct, cries out to be redressed. It should not have taken a federal judge's order -- and two years of litigation -- to get the government to undo the effects of its own wrongdoing.