IN A STRIKING display of pedestrian leadership, Gov. John N. Dalton has managed to parlay a short-sighted understanding of a bill into a way to cuff Northern Virginia again-this time with a veto. Though the bill he killed could be considered small, so could governor's reasons for acting as he did.

The whole idea, originally sponsored by Sen. Edward M. Holland (D.-Arlington), was to start doing something about non-resident motorist who park illegally in Virginia. The modest measure, supported by the Northern Virginia Transportation Commission and the Metropolitan Washington Council of Governments, simply would have given the governor authority to enter into reciprocal agreements with the District of Columbia and states bordering Virginia, for the collection of parking fines.

But in his thoughtful two-sentence veto message, Mr Dalton contended that reciprocal agreements somehow "would increase administrative costs and cause considerable public difficulty in the Northern Virginia area." He also expressed "concern"-get this-that erroneous recordings of license-plate numbers by officers issuing tickets could lead to attempts to collect fines from innocent motorists. Now, you can't argue with that narrow logic, though it's hardly a ringing defense of law enforcement.

More to the point, if less apparent in the governor's explanation for his veto, was the candid reason given by opponents of the measure in the House of Delegates-namely, that Virginians have piled up more unpaid tickets in D.C. than the other way around. This ignores the arguments of Arlingtonians that, if they could collect the fines of D.C. and Maryland motorists who park illegally, the county would come out ahead in a reciprocal arrangement. So in vetoing the bill, Gov. Dalton not only has rejected an opportunity to negotiate some fair agreement-but he also has given his implied consent to scofflaw parking by looking the other way.