Virginia's ranking Republican state legislator, citing the party's defeats at the polls this month, said today that the GOP must broaden its base and reach out to blacks and women.

Del. A. R. (Pete) Giesen of Augusta County said the Republican Party of Virginia should be "a party of inclusion" and should exclude neither the Christian Right nor the followers of former governor Mills E. Godwin, a one-time segregationist. Both groups have been blamed by some for the party's defeats in the Nov. 5 elections.

Giesen, chairman of the Republican Legislative Caucus, said the Democrats won the state's three top offices because they did "a more effective job" in selling their nominees for governor, lieutenant governor and attorney general.

But the Shenandoah Valley Republican conceded "there is enough blame to be spread around" for the losses and said they could not be attributed to "just any one thing."

"A Democratic victory, based on maintaining the status quo, does not undermine the basic strengths, nor invalidate the message, of the Republican Party," Giesen told a news conference at the state capitol.

The Democrats did not add to their 65-seat majority in the House of Delegates, although Republicans lost one seat to an independent, Giesen noted. That will give the 100-member 1985 "There is enough blame to spread around" in statewide GOP losses. -- A.R. (Pete) Giesen House 65 Democrats, 33 Republicans and two independents.

Giesen, who had unsuccessfully sought his party's nomination for lieutenant governor, surprised some with his analysis of the voting, saying that a larger-than-expected turnout of blacks was a factor in the Democratic victories.

He said that a large turnout of women and black voters, along with flooding in rural areas, "alone may have added 4 or 5 percent to the margin" by which Democrat Gerald L. Baliles beat Republican Wyatt B. Durrette in the race for governor. Most analysts have said that the black turnout was much lower than expected.

Baliles will take office Jan. 11, along with his running mates, Lt. Gov.-elect L. Douglas Wilder, the first black to win a major state office in the South, and Attorney General-elect Mary Sue Terry.

Del. Frank D. Hargove of Hanover County said the party "is on a course to not exclude anyone, the Christian Right, blacks, women or Mills Godwin. We want a diversity of views. We're not going to tell senior members of the party they are no longer acceptable. Mills Godwin is very acceptable."

Hargrove and Giesen rejected calls to read Godwin, a former Democrat turned Republican and the only man twice elected governor of the state, out of the party. "This is no time for this party to ask anyone to leave, but to come to it," said Hargrove.

Giesen said he plans to speak around the state in the next two weeks, seeking to set a conciliatory tone for the party's upcoming conference in Staunton Dec. 6 through 8.

He urged Republicans to resist the temptation to "listen to our party's righteous saviors who preach nothing less than bloodletting. I say to them: 'If you are without fault, cast the first stone.' " And to Democrats, he cautioned: "There is no more dangerous an animal than a slightly injured elephant."