IN A BOLD demonstration of provincialism, eight of Fairfax County's supervisors have voted to wage a narrow-gauge attack on Metro's regional transit system -- complete with the old blackmail threat to withhold money owed until they get their way (or finish playing up to sectional interests, whichever comes first). They're saying they won't render their quarterly payment, which was due Friday, until the Metro board approves a fare increase. Only Supervisor Joseph Alexander, who serves on the Metro board, had enough regional sense at least to abstain, observing that the supervisors' move "isn't going to help."

On the same day, the supervisors also decided that the county should begin running its own public bus system. Unlike the blackmail attempt, this decision has some long-term merit, even if this week's vote was ill-timed for political effect. Throughout the region there is unhappiness with Metro's labor costs and its ability to provide good local bus service beyond main lines. In Montgomery County, for example, the Ride-On system runs more than 90 buses and has 52 more on order. Other jurisdictions are looking at similar local bus system plans.

Metro general manager Richard Page has noted that the regional system does not oppose decentralization, pointing out that local control of buses may be more efficient. But decisions to break away should not be taken helter-skelter, without consideration for money Metro already may have committed to equipment and personnel. There is no question that Metro's contractual labor costs are forcing new thinking in every jurisdiction; either there will be some adjustments, or the number of jobs will be cut and replaced by local operations.

Still, none of this excuses the reckless shenanigans of the supervisors, who know perfectly well that fare increases are as inevitable as their obligation to turn over the county's payment.