BY NOW WASHINGTON has come to expect irresponsible statements-and behavior to match-from school board member Frank B. Shaffer-Corona. And his latest outburst did not let us down: It was a mindless slur on Prince George's County.

Mr. Shaffer-Corona's previous contributions to the city have included writing letters on board stationery to the vice president, secretary of state and attorney general of the United States, criticizing their policies toward Mexico and immigrants; trying to travel to Mexico at public expense to meet with that country's president; succeeding in traveling at the school system's expense to a youth festival in Cuba and, earlier this year, making offensive remarks about Jews and their relationship to one of the school board members.

The nasty crack at Prince George's was delivered during "Awareness Day," an occasion that Mr. Shaffer-Corona and colleagues on the board created to celebrate the Wilmington 10, in keeping with the board's wrongheaded habit of inserting itself and the city's schoolchildern into various campaigns and causes. Speaking to an assembly of prominent local officials as well as 12th-grades at Dunbar High School, Mr. Shaffer-Corona said, "Education is liberation, if you want the skills to get a decent job, if you don't want to get pushed out into that police state P.G. with a bunch of trigger-happy cops."

In reply, County Police Chief John W. Rhoads has properly noted that "such a statement from a public official is repugnant. I certainly agree with School Board President Minnie Woodson that some of your remarks were inflammatory and, I add to that, politically self-serving and not in the interest of ridding this country of racism. . . . As a public official you have many obligations to uphold and meet. One of them is not making statements with a reckless disregard for the truth."

Mr. Shaffer-Corona owes Prince George's an apology. He is demonstrably unfit for the responsibilities for which he was elected. The least he could do would be to stop making wild and ugly statements.