THE NEW OFFICE of Maryland state prosecutor is supposed to open July 1 but Gov. Martin Mandel hasn't even formally appointed the commission that's supposed to pick the prosecutor. And guess what seems to be holding up this move? Not the governor's health problems - but good old politics.

The commission is a seven-member body that actually has already been chosen by various parties according to a formula. Under this procedure, the governor may reject a nominee only for cause; otherwise he oppoints him. The politics here has to do with two Democrats who both want to run for governor next year. One, Attorney General Francis B. Burch, is automatically a member under the formula - but he wants to be chairman of the commission. The other, state Senate President Steny H. Hoyer of Prince George's County, who was instrumental in establishing the new prosecutor's office in the first place, doesn't think the commission should be headed by a candidate for top political office.

Neither do we. To begin with, the job wasn't meant to be used for political gain. On the contrary, the whole process was designed to guard against this very sort of abuse. For example, the prosecutor, once chosen, is prohibited from seeking an appointive or elective office until three years after his or her term expires. Anyway, Mr. Burch surely has plenty to do already as attorney general and political candidate without taking on the chairmanship of this new commission.

All Gov. Mandel needs to do is formally appoint all the members and pick one who isn't Mr. Burch to be chairman. Yet in addition to stalling, the governor reportedly is considering just appointing the commission and letting it choose a chairman - thus evading his responsibility, inviting still more political infighting and, for all we know, allowing statutes of limitations to expire on campaign abuses of the past.

In a state where the trust that voters place in officials has been abused so often, this sort of political funny-business threatens to taint the one important new effort aimed at cleaning up heretofore uninvestigated corruption. If Gov. Mandel can't handled the simple chore of appointing the commission and naming a chairman, he could at least pass the pen to Lt. Gov. Blair Lee III so the prosecutor's office can begin in its work cleanly and on time.