YOU DON'T HEAR any sounds of gunfire, or much of anything else, around the Manassas National Battlefield Park these days, but there happens to be quite a fight in progress there - and it's the silence that may wreck the area. If the historic acreage surrounding the park turns tourist-trap-tacky, it will be because Virginia's two senators never spoke up for legislation that would preserve the area. And their excuse will likely be that the Prince William County supervisors - who lick their chops at the thought of any development, no matter how disgraceful or wherever it might go up - refused to hold any hearings on the matter.

Here's a summary of what's not happening. A bill that was passed by the U.S. House is stuck in the Senate; the measure, sponsored by Rep. Herbert E. Harris (D-Va.), would expand the park periphery, protecting such historically valuable sites as the acreage around Stone Bridge over Bull Run - where a Confederate general named Jackson acquired the nickname "Stonewall" - and a clump of shrapnel-scarred trees marking the site of the village of Groveton, which was destroyed in the second battle of Manasas. The reason for the Senate's inaction on the bill? Sens. William L. Scott (R) and Harry F. Bryd (I) have requested delays.

Sen. Scott, as some may recall, single-handedly blocked Senate passage of the bill the last time the House passed it - exercising a proxy in the closing hours of the last Congress while he was off on a trip to the Philippines. As for Sen. Byrd, he's been telling concerned residents and historians that the county board should hold hearings before the Senate acts - even though he knows full well that the county supervisors are refusing to allow any official consideration of the matter. As a senator with a record of concern not only for Virginaia's heritage but for conservation in general, Mr. Byrd could be instrumental in moving the bill - in putting greater historical interests ahead of reckless development fever at the local board level.

As an editorial in one local newspper, the Journal Messenger, put it: "The manner in which this issue is being handled by the board strikes us as a very irresponsible display of vested authority." Only one of the seven supervisors, Kathleen Seefeldt, has expressed any interest in even listening to local opinion on the measure. Thus, six stubborn supervisors and two senators are managing to block legislatoon of national historical importance. Even if you consider the supervisors and Sen. Scott as beyond redemption when it comes to judgments such as this, Sen. Byrd should recognize obstructionism and work to overcome it by leading the campaign to enact the Manasas Battlefield preservation bill this year - before permanent damage is done.