Since a jury found John Hinckley Jr. not guilty because of insanity in the shooting of President Reagan, U.S. District Court Judge Barrington D. Parker says he's received about 1,500 letters, some with racist overtones and most blaming him for the acquittal.

Parker discussed both the public's and his own reaction to the jury's verdict in an interview last week with the Independent Television News Association.

In most cases, even highly publicized ones, judges rarely get more than a handful of letters. Judge Harold H. Greene, for example, got about 50 letters, officials said, after he announced his decision in the AT&T break-up case. One exception to the rule, observers say, was the roughly 20,000 letters Judge John J. Sirica received during and after the Watergate trials.

Parker, who is black, told reporter Val Hymes that some of the letters have "a nasty little thread of racism running through them" and an "overwhelming" majority "castigated" him for the acquittal because of the jury instructions he gave on the insanity plea.

Parker said those who wrote the letters "think I allowed Hinckley to go free." He said the public did not seem to understand a judge's role: "I don't make the law, I follow the law."

Parker said he was not exactly shocked at the verdict, but that he was surprised by it. "I thought the government put on a good case," he said, but at the same time pointed out that Hinckley's father, a wealthy Colorado oilman, had spent several hundred thousand dollars to mount an impressive defense headed by Williams & Connolly lawyers Vincent E. Fuller and Greg Craig.

Parker said he had presided over three earlier insanity defense cases and all those were convictions.