Life and times in the Old Dominion - the Commonwealth of Virginia - have reached a new plateau.

This venerable capital, until so recently a citadel of the Solid South, now supports a Republican hamburger joint.

A Republican hamburger joint in Richmond is just as you would imagine it. The gold lettering on the plate glass window tells you it is named "W.T. O'malley's," for a nonexistent Irishman, and suggests in a subtitle that it is "An American Pub."

Behind the window is a walnut-stained interior that reassures the clientele from Richmond's financial district that to go to lunch in 1978 one need not step out of the era of Coolidge, or even McKinley.

A 38.5-foot-long standup bar with a brass foot rail is presided over by O'Malley's only female employe, Merrill Wall, a tall Kentuckian who prepared for her role as elegant matriarch of O'Malley's bar by majoring in English and earning four letters in field hockey at the University of Virginia.

She deals out six-bit beers in frosted mugs to patrons and to an equally overqualified force of waiters clad in white aprons and black bow ties. Among the latter are Ronald P. Vigneault, a playwright who has a Ph.D. degree in theater, portrait artist John Court, whose painting of Secretariat hangs opposite the bar, and Horace E. (Chip) Mann, a 23-year-old member of the William and Mary College Board of Visitors.

The waiters, bearing straw baskets of fried potatoes and hamburgers with a base price of $2.50, glide between tables covered with green and white checkered cloths. This is not McDonald's.

Presiding over all is restauranteur Gerald K. Waters, 41, former advance man for Nelson Rockefeller and Robert Dole, finance director for Governor John N. Datpm's campaign and now finance director of the Republican Party of Virginia.

When Waters came back to his native city after the 1976 campaign, he perceived a void in the capital's downtown restaurant offerings that he thought could be filled with a simple beer and hamburger menu served in an atmosphere that would induce people to hang about and talk.

He envisioned a restaurant with at least the flavor of a Clyde's of Georgetown of P. J. Clarke's in New York. Patrons of instant name and face recognition that help sustain the reputation of such big city cafes are in short supply in Richmond, but Walters is doing the best he can with those who are at hand.

Most famous of the O'Malley regulars is the Richmond News Leader's syndicated cartoonist, Jeff Macnelly, but his presence has to be discounted by the fact that he has a financial stake in the venture.

The cadre of young Republicans who have found hope of permanence in Richmond after a string of successes in statewide races, have turned O'malley's into a restaurant where you can by sure to encounter political gossip.

Waters and another partner, Dalton campaign manager and press secretary William A. Royall Jr., give the management a Republican flavor, but Waters keeps up a bipartisan front. Pictures of Democratic Lt. Gov. Charles S. Robb and state Democratic chairman Joseph T. Fitzpatrick adorn the walls beside Republican political figures.

If O'Malley's succeeds in becoming a headquarters for convivial political exchange in Richmond, it will have accomplished a useful social mission. It is not uncommon in this capital, which almost always serves as the statewide headquarters for every major political candidate, for the competing campaign staffs to go through an entire race without meeting each other.

Royall, for instance, ran former President Ford's successful Virginia campaign in 1976 without ever encountering Timothy Smith, who labored as leader of the Carter campaign at a headquarters only three blocks removed.

If O'malley's succeeds in becoming a public house for such campaign figures and officeholders in the tradition of the old Williamsburg taverns, one can only wish waters and company good luck and lots of competition.