IT IS NO ACCIDENT that here has long existed throughout this region a strong strain of enlightened public serivce -- tradition of civic contribution and cooperative vision that has enriched the quality of local government. Call it good fortune, perhaps, but it stems in no small way from the achievements of a remarkable Maryland family, whose tree has had its roots in Montgomery County for the last 140 years: the Blairs and the Lees, who saw -- and guided -- the evolution of Montgomery from lush rural contryside to model suburban county. A special champion in this long line of exceptional achievers was Elizabeth L. Scull, who died yesterday of cancer at the age of 57.

While devoted to her famous family, Mrs. Scull was not blindly loyal to her heritage as she moved through a lifetyime of non-stop public service. On the contrary, her sense of good, suburban politics and regional cooperation took her across partisan lines and predictable alliances to independent, thoughtful efforts to improve the living conditions of everyone in general and the poor in particular.

With her husband, the late David H. Scull, she took the best of her family tradition, long steeped in Democratic politics, to a then-minuscule Republican Party, which the two of them developed into an organization singularly adapted to the suburban politics of thankless civic work: the endless meetings, squalid quarrels and collisions of greed from which would eventually emerge a civic commitment to highly democratic, responsive government equipped to establish and maintain strong systems of schools, parks and planning.

After her husband's death, and after the Republicans rejected her in favor of someone else to complete Mr. Scull's term on the county council, Mrs. Scull returned to the Democratic Party, won election in 1970 with overwhelming support -- and never lost again. Housing would remain her special concern during service on the council, as member of subcommittees and as a leader in the Metropolitan Washington Council of Governments -- where her contributions to regional governments approaches won her areawide respect and affection.

As COG president Stephen H. Detwiler, chairman of the Arlington County Board, said yesterday, Betty Scull "was forceful yet gentle, farsighted yet practical, a politicla leader in the noblest sense of that term."