SHORTLY AFTER MARVIN MANDEL made his brief post-verdict statement in Baltimore, the man who is succeeding him - Blair Lee III - had a few things to say from the State House in Annapolis. "This is a sad day for all of Maryland," the acting governor begain. "As a human being I am profoundly affected by the verdict." And he went on to promise that "the job of carrying on state government will go on without interruption or consternation or confusion." That was really about all that people needed to hear at this dramatic moment in Maryland's history - but unfortunately, it wasn't all that the acting governor had to say.

Mr. Lee, who's had a bit of time throughout these last weeks concealing his exuberance at the prospect of being chief executive, couldn't resist cutting some political distance between himself and the man to whom he had been demurring so loyally during the Mandel-Lee administration. Moral leadership, Mr. Lee observed, was probably never one of Marvin Mandel's "superstrong points. He just never believed in candor, and without candor you have a problem. Being a good governor isn't quite enough . . ."

Now that's an awfully sudden leap over the side by a shipmate when the skipper's in extremis. Just when did Mr. Lee first notice that the man he has so often praised to the skies was short on moral leadership, candor and honesty? True, one could chalk this off to Mr. Lee's chatty ways. And certainly his description of the fallen governor may be on the mark.But the comments, coming when they did, were remarkably graceless.

Having now endured two consecutive governors who ran trouble with the law, the people of Maryland could have done with a bit more reassurance from Mr. Lee and a little less born-again political piety at the expense of his longtime colleague - a man for whom he had been a vigorous lobbyist and articulate spokesman. Blair Lee's business at the moment is self-evident: It is to restore a measure of dignity and sensitivity to the office he inherits. His remarks about his predecessor go in the other direction.