IT TOOK A PUBLIC outcry about sluggish police response times, plummeting officer morale, a barrage of bad publicity and, finally, a murder spree last month. But at last the leadership in Prince George's County has gotten serious -- or at least mostly serious -- about beefing up the severely undermanned police force. County Executive Jack B. Johnson, who declared two years ago that he would dispel police suspicions about him, took a step toward fulfilling that promise by unveiling a six-year plan to give the police department what it needs most: more officers in uniform.

This is a badly needed step in the right direction. At the moment Prince George's has about 1,300 officers, 120 fewer than its authorized strength. But that level was set nearly 15 years ago, and, considering the county's swift population growth, it is irrelevant. In fact, the county needs hundreds more officers, and that is what Mr. Johnson proposed.

We say the initiative is "mostly serious" because in announcing it, Mr. Johnson was slightly disingenuous about the numbers. He proclaimed that the county would hire, train and equip 150 officers in each of the next six years, assuming he is reelected to another four-year term in 2006, for a total of 900. But he did not mention that about 85 officers quit or retire from the force each year, a number that may increase somewhat as the pool of those eligible for retirement grows. With some recruits already in the pipeline, the net increase by 2011 is expected to be 500 officers, bringing the force to around 1,800. That's about the size of the force today in Baltimore County, a jurisdiction similar in size and population to Prince George's -- but with much less crime.

Still, Mr. Johnson's commitment is substantial, and it comes with a substantial price tag: The police budget, now $159 million, would have to grow by about $7.5 million a year, well over the rate of inflation.

The plan is not without risks. Police brass in Prince George's, mindful of painful experience in the District and elsewhere, want to avoid a rush to hire warm bodies and the resulting degradation of a police force that has had more than its share of problems in the past. Nonetheless, if managed carefully, Mr. Johnson's proposal should go some distance toward addressing the law enforcement needs of a jurisdiction dogged by crime problems it can ill afford.