The Democrat-controlled Virginia General Assembly, unwilling to seize the opportunity for a major partisan coup, adopted a redistricting plan today that fails to loosen the Republican Party's stranglehold on the state's 10-member U.S. House delegation.

Buffeted by their own intraparty strife and seemingly happy with the conservative congressmen that Virginia has sent to Washington, the Democrats ended a three-day special session with an ironic gesture. They had to ask Republican Gov. John N. Dalton for help on correcting population inequities that otherwise could throw their plan into court.

The issue gave the Democrats, who have a three-to-one majority in the legislature, a once-in-a-decade chance to redraw the state's congressional boundaries to the lasting detriment of Virginia's nine GOP representatives. bBut it was an opportunity the Democrats refused to grasp.

Some Democrats said many of their colleagues were too satisfied with the members of the Virginia delegation -- regarded as one of the most conservative in Congress. "There is no question, at least on the House side, some Democrats were anxious to take care of the good old Republican boys they work so closely with," said Sen. Elliot S. Schewel (D-Lynchburg).

"Several plans designed explicitly to shaft the Republicans met resistance from a hell of a lot of Democrats." Schewel said. "It doesn't make any sense on a political basis, but each legislator does what's in his own best interests in his district, and that transcends the party."

Del. Mary Marshall of Arlington was among some Democrats dismayed at the failure, which she blamed on a void in the legislature's leadership. "If a Martian dropped down in front of you and said 'take me to your leader,' what would you do?" The answer, she said, is that nobody knows who the leaders are.

Lt. Gov. Charles S. Robb Jr., who is unopposed for the Democratic nomination for governor, presided over the Senate as crucial decisions were made today, but played virtually no role in the process.

Several times, Senate Majority Leader Hunter B. Andrews (D-Hampton) huddled with legislative leaders in Robb's office just off the Senate floor, while Robb remained on the rostrum, awaiting their return to gavel the chamber back to order.

While state legislatures historically have used redistricting as opportunity to strengthen the majority party's chances in congressional elections for the next decade, there were few cries of gerrymandering from Republicans as Virginia Democrats bickered among themselves.

While some younger House Democrats argued for a partisan plan that would place Northern Virginia's two Republican congressmen in the same district, the adopted plan makes no boundary changes in the region's 10th Congressional District and only minor changes in the adjoining 8th District.

The approved plan drops western Prince William County, the cities of Manassas and Manassas Park and a portion of Spotsylvania County from Rep. Stanford Parris' 8th District and adds it to Rep. Kenneth Robinson's 7th District. The result, some Democrats complained, will be to give Rep. Frank Wolf of the 10th and Parris relatively safe districts.

Recent population growth in Virginia's suburbs has brought new life to the state's Republican Party, which had taken a back seat to the Democrats since the end of the Civil War. Although the Democrats continue to dominate the legislature, with a 74-25 advantage in the House and 31-9 in the Senate, they have not won a majority of the state's vote for governor, senator or president in more than a decade.

"The Democratic Party hasn't caught on to its problems yet," said Marshall. "It's actually threatened by the Republican Party, and unless it gets its act together it will lose elections."

Members of the Virginia House had sought to block a Senate-drawn redistricting plan today by declining to approve amendments to the bill that had been worked out in a conference committee, arguing that Senate Majority Leader Andrews had acted in bad faith by refusing to allow House conferees to introduce substantial changes in the plan.

"Hunter stepped on everyone's toes," said Del. Warren E. Barry (R-Fairfax). "He just walked in like a bull moose and everyone resented it."

But the Senate, led by Andrews, suddenly approved a House-approved version of the same plan and sent it to Dalton, thereby cutting off House attempts to tamper with it. At the same time, the senators sent a resolution to the governor asking him to return it to the legislature this summer with specific amendments that will bring it in line with constitutional requirements for equal representation.

Population deviations in the plan ranged up to 2.56 percent between districts, and some legislators said that is more than federal courts have been willing to accept. The deviations in the congressional plan, however, are far less than those in the Virginia House's own reapportionment plan -- a proposal that is espected to be challenged in court later this month.

One Democratic senator tried to credit Robb, the Democrats' candidate for governor, with behind-the-scenes maneuvering in a closed-door meeting last night, but Robb declined the honor, saying he was "involved only in procedural rulings." Robb, who is trying to portray himself as more acceptable to conservatives that Republican J. Marshall Coleman, his likely opponent, said, "I'm loyal but not blindly partisan.

"The legislature approached it [redistricting] on a bipartisan basis, as it does most matters. It would be essentially out of character to adopt an intensely partisan modus operandi," said Robb.

On the other side of the Capitol, House Speaker A. L. Philpott puffed on his pipe, swiveled in his chair and did little to halt the intraparty squabbling that overshadowed partisan concerns.

"You've got to realize that there is never going to be a plan that everybody is satisfied with," said Philpott. "I knew I had to take my lumps with everyone else." Philpott had opposed the Senate version of the plan because it places predominantly Republican Carroll County into his congressional district, which has Rep. W. C. (Dan) Daniel, the state's only Democratic representative.

After the Senate took the final action, Andrews congratulated the Assembly for being "the first in the nation to complete the redistricting task," which is required after every census. Despite Andrews' comments, the task probably won't be completed until after a June 3 session in Charlottesville.

Legislative leaders then expect the assembly to consider revisions to the congressional plan that Dalton was asked to make. The governor told a news conference today that he hasn't considered the issue yet, but he added: "I wouldn't be at all surprised I wouldn't be sending some amendments down."

Democrat Andrews said he believed the entire process had been handled swiftly and fairly. "We have accomplished the entire reapportionment [congressional and legislative] in fewer days than ever before." In 1971, he said, the process lasted from February to July.