OF A PIECE with Rep. Charles Wilson's overstepping of the home rule line this week was a vote by the House Appropriations Committee. It voted to restrict city government attempts to cut the number of policemen as a budget-trimming manuever. The prohibition has the effect of setting a budget priority for the city government. The police department can now maintain a staff of about the current size, no matter how short the city may be of cash. The committee vote follows longstanding concern from Congress over the size of the police department. Some members of Congress have long made it clear that they consider the work of the city police to be the most important municipal service.

In truth, the police department is in need of some special attention at this point in its history. The department is in the throes of major change. It is losing more than 230 police officers by the end of this month, and those officers have been key to the department's success. They include people such as the head of the fingerprint operation, the chief of detectives, and the head of the special operatioans division, the group that handles the frequent demonstrations in the nation's capital. With those people and others leaving, the department is losing much of its knowhow. Add to that problem a steep rise in crime in the past few months and some interdepartmental uncertainties over how white officers are being treated in an increasingly black department, and it becomes apparent that the police department cannot stand sharp budget cuts at this time.

But Congress is not the body that should be making that decision for the District government. If the department needs help, the mayor and city council should be the ones to make a decision to help it.