JUST WHEN thoughtful law enforcement officials around the country are turning away from the old build-bigger-fortresses answer to their swelling prison-population problems, Virginia Gov. John N. Dalton is getting set to push a huge brick-and-mortar prisons budget on the legislature. As staff writer Karlyn Barker has reported, the governor proposes to stick taxpayers with a bill for $80 million over two years for construction work on five new prisons and repairs on old ones. Though even his own director of corrections thinks prisons "are an expensive way to protect the public safety," the governor contends that taxpayers will buy it. Says a Dalton aide, "We don't think his program is going to appear excessive to anybody."

That is as nonsensical as the proposal itself, which flies in the face of enlighted corrections policy, not to mention fiscal prudence. State Corrections Director Terrell Don Hutto said months ago that unless Virginia changed its prison policies, construction could cost more than "taxpayers can reasonably sustain." He and other thoughtful experts have been studying prudent ways to reduce their prison populations -- a more sensible approach, but one that many politicians still hesitate to advocate publicly.

Though it costs more to keep on building and packing big prisons, it's cheap as political shots go: the office-seeker simply says, as the state's own attorney general has, "if I have to choose between spending more money to build more prisons and putting dangerous criminals back on the street, I'll choose the prisons." But that's not the choice, and he more than most should know it. The sensible, fiscally conservative alternative is to do something about lawbreakers who are not dangerous, who have been convicted of nonviolent crimes.

Mr. Hutto believes that 70 percent to 80 percent of Virginia's inmates could be diverted to more effective local community programs without risk or increased cost to the public.Instead, Virginia now ranks 12th nationally in the percentage of its population it locks up, and 10th in the length of its prison sentences. For the most part, the treatment of those who are locked up has been a failure. Too many have been returned to society more embittered than when they left it.

This is why some informed legislators are critical of Gov. Dalton's plan. Del. Frank Slayton of South Boston, a former county prosecutor, is one; he argues for more local programs, including work-release plans like those adopted successfully in other states. Del. Erwin (Shad) Solomon, a member of the Virginia Crime Commission, is another who prefers alternatives to across-the-board incarceration. The sooner others in the state realize it, the better. Today's jam behind the bars has got to stop -- for reasons not only of humanity and cost, but of public safety as well.