Party unity has never been the strong suit of Democrats, but Virginia Gov. Robb barely had time to hang up his jacket and sit down before all partisan hell broke loose. Yesterday, the Democratic bandwagon he built last fall lost a tire on the way to the next big statewide election: Owen Pickett--Mr. Robb's handpicked candidate for the U.S. Senate seat being vacated by Harry Byrd Jr.-- dropped by the wayside after a series of intraparty maneuvers had crippled his candidacy.

Score one for State Sen. L. Douglas Wilder, Virginia's top black politician, whose threat to bolt the party and run for the U.S. Senate as an independent has clearly shaken and almost cracked Gov. Robb's fragile coalition of older-line and newer-South Democrats. After a few unproductive huddles called by Mr. Robb, candidate Pickett tried to smooth things by releasing his pledged delegates to the party's nominating convention in Roanoke next month. But Mr. Wilder and other party members--still unenthralled by Mr. Pickett's candidacy and angered by what they consider Democratic insensitivity to concerns deemed important to blacks--held out for more, and got it with news of Mr. Pickett's withdrawal.

Has it damaged Gov. Robb's party influence or handed the election to Republican Paul Trible? Stay tuned for today's scheduled word from Mr. Wilder; if he and the governor share as many concerns about their party's future in Virginia as they do about a more representative role for minorities in the state, the two of them will pick up the pieces together, and the Democratic wand will tap a candidate who can help to close the ranks. Otherwise, continued disarray is sure to cost the party dearly.