ONLY DAYS AGO we were noting in this space how refreshing was the sharp focus of the Senate campaign in Virginia - the candidates' concentration on issues - as well as the impressive resurgence of the Republican Party in the state. On both counts, most of the credit belonged to Richard Dudley Obenshain, the hard-driving GOP candidate for that Senate seat. Wednesday night, Mr. Obenshain's prodigious effort to reach a new peak in political accomplishment ended tragically in his death at 42 in a plane crash. And just as suddenly, the fruits of his political labor - both the sharpened campaign and the new-found unity and strength of his party statewide - seem to have vanished as well, leaving uncertainty and disarray, however temporary they turn out to be.

With good cause, many a partisan colleague along the campaign trails used to introduce Dick Obenshain as "Virginia's Mr. Republican," for clearly it was he who early on saw a new role for his Grand Old Party, and who spent 18 highly active years of organizing and shaping its growth. Under his leadership, including terms as state chairman and co-chairman of the Republican National Committee, the party emerged from nearly a century of being out of power to attract and build a base of constituents. Mr. Obenshain saw a place for the new Virginians - the middle-management experts who were moving into the state - alongside the well-heeled, established remnants of the old Byrd Democratic organization's heydays.

It was Mr. Obenshain who helped engineer the conversion of Mills E. Godwin Jr. from a former Democratic governor to a Republican governor; and who worked to elect John N. Dalton lieutenant governor and then governor. Moreover, Mr. Obenshain's self-professed and deep conversatism - patterned in the image of one of his heroes, Sen. Barry Goldwater - was by no means a political liability around the state; he succeeded in appealing to an increasingly larger constituency, as demonstrated two months ago in his nomination at a spectacularly large and exhilarating GOP convention in Richmond.

But now that exhilaration is gone as members of the party's state committee grope to settle on a successor. There is no immediate way of knowing how this unfortunate turn of the events will affect the Senate contest or the strength of the Republican Party. But the sudden loss of Richard Obenshain extends beyond immediate partisan considerations - to all who still appreciate the impact his efforts had on the development of state leadership over the years.