Ever since the days of powdered wigs and feathered pens it's been the cardinal rule of politics in this state of history- makers: Whatever you say or do, don't embarrass Virginia. And though the Democrats who convened here made big history by nominating a black and a woman to their top state ticket, any rocking of the boat was deftly genteel.

Close your eyes, and you could call it mainstream:

No one on this ticket has ever lost a campaign.

The party nominee for governor is currently the state attorney general in the administration of one the most popular governors in a long time. Before that, the nominee served six years in the House of Delegates.

The choice for lieutenant governor has more legislative experience than the last five lieutenant governors combined. He is an acknowledged leader in the very legislative body over which he would preside if elected, having served in the state senate for 15 years and been chairman of three of its most important committees and member of a fourth. He talks about "pragmatism, individualism and effectiveness through old-fashioned hard work -- P, I, E -- three fundamental values as American and as Virginian as apple pie."

The nominee for attorney general is a veteran of eight years in the House of Delegates, the only candidate who has served as a prosecutor in the Courts of the Commonwealth and one who talks reverently of "good, sound government that's predictable, and where the people do what they say they're going to do. That's what Virginia's all about. Together we want to put the voters of Virginia in the best position to make judgments."

Hardly the stuff of rabble-rousers. A dream ticket in almost any other state. And propelled from this convention in bursts of rare unity and high praise. Gov. Charles Robb, whose legacy they relish, calls Attorney General Gerald Baliles, State Sen. L. Douglas Wilder and House Del. Mary Sue Terry "three able and talented Virginians with a clear edge in leadership and experience." And by acclamation for all three nominations, the convention delegates called them the party's ticket to a state house sweep in November.

But what will all the voters across this vast and varied commonwealth call these candidates? Spoken or unspoken, attitudes toward race and sex will be factors, though no one really knows to what degree.

Ticket for ticket, the Democrats have an acknowledged edge in experience and talent. The Republicans, having bowed to the wishes of their Old Guard coalition of Early Byrd Ex-Democrats and self-professed super-conservatives, have saddled their nominee for governor, Wyatt B. Durrette, with two good-natured but relatively undistinguished running mates: State Sen. John Chichester for lieutenant governor and House Del. W. R. (Buster) O'Brien for attorney general.

Baliles and Durrette did battle against each other four years ago in the race for attorney general, with Baliles the victor. Each is prepped and eager for another round, with valuable help: Baliles with Robb, and Durrette with President Reagan all but signed for campaign duty. And each enjoys the unified enthusiasm and support of his party.

And though Democratic delegates are not naive enough to believe that Wilder and Terry won't encounter opposition that has nothing to do with their abilities, they view the Republican choices of Chichester and O'Brien as the best gifts they could have been handed. "Just let 'em go one-on-one in debate," said one state legislator who has watched Wilder, Chichester, Terry and O'Brien in the General Assembly. "Doug can make mincemeat out of Chichester, and Mary Sue and Buster is no contest." Another lawmaker, referring to Chichester as a lackluster politician with nowhere near the expertise of Wilder, said, "Better to be black than gray."

The underdog in all this, and he's the first to acknowledge it, is Wilder. Already he is tagged as "liberal," a label some Virginians automatically attach to anybody who wants to change anything -- and that includes the color of those who have served as lieutenant governor. Wilder dismisses the label as meaningless and inaccurate by any stretch of a definition, anyway. "I have not asked for armies to come into the state to get fair housing passed, or to campaign for Martin Luther King's birthday as a holiday, or for help against sickle-cell anemia. When I came to the senate of Virginia, I asked for no special favors or benefits. All I wanted was to be judged by the same standard that had been used to judge every other senator privileged to serve in that august body. . . . Virginians are looking for preparation, a good record, accountability."

If his running mates are at all nervous about his being on the ticket, it is nowhere evident. On the contrary, Baliles and Terry are talking pride in the whole ticket, and Wilder says it's been that way from the beginning; and Robb told the convention delegates that another Democratic sweep is "important to me, it's important to you and it's important to Virginia."

But it's the last thing that another governor -- former Gov. Mills E. Godwin, supreme ticket-builder for the GOP and revered voice of the older Old Dominion -- wants to see happen. And right now, that may be the greatest pressure on Durrette: to crank up his own running mates -- and deliver.