To many Virginians, Rep. M. Caldwell Butler is best known for his votes on the House Judiciary Committee to impeach his fellow Republican Richard M. Nixon.

The other week, while most political attention was focused on the state's general elections, Butler cast another vote in the judiciary committee and it was one that some say Butler may not soon forget.

What Butler did was vote against a Democratic amendment which would have added 33 federal judgeships to 80 new judgeships a subcommittee had approved.

"It was the damnedest piece of log-rolling I've ever seen," said Butler, who has been in Washington representing the Roanoke area since 1972. It took "an act of political courage" to oppose it, he said immodestly.

All of which might sit well with his constituents except one of those judgeships was to have been in Roanoke and would have served in what one of Butler's colleagues has described as one of the most overworked court districts in the nation - the western Virginia district.

What's more intriguing is that the Virginian on the indiciary committee arguing for the judgeship is Rep. Herbert E. Harris, the Northern Virginia Democrat whose congressional district is entirely within Virginia's eastern judicial district where two new judgeships are due to be added under legislation previously approved in committee. Harris has claimed through a spokesman that until shortly before the committee vote Butler was supporting the need for two judgeships in his area.

To many congressmen, voting for plums like judgeships are automatic as favoring more federal spending in your own district. After all, the man who gets the judgeship could be a political supporter and lawyers, who tend to be political activists, usually like the idea of getting yet another judge to practice before.

Virginia lawyers have been jokeying for such judicial appointments ever since it became apparent last year that the state was likely to get up to four new federal district judges. Under a Senate-passed judgeship bill, two of the judges would serve eastern Virginia and two, western Virginia.

But then a House judiciary subcommittee trimmed one of the judgeships from the western half of the state and 29 others from various parts of the country. Enter Harris and Butler.

Normally you'd expect some partisan feelings on such an issue. With a Democratic President in the White House, making the appoinments, Harris should be for the new judges. But remember this is Virginia and one man who is certain to have a major say in the judgeship is Sen. Harry F. Byrd Jr., who is not your average Democrat.

Byrd is a Democrat only in the sense he votes to organize the Senate with the Democratic majority. When Byrd ran as an Independent last year, Harris worked hard to defeat him.

Indeed, the way Harris' press secretary, Jack Sweeney, describes the judgeship dispute, it was Butler who induced Harris to push for restoring the second judgeship.

"We came into this in support of Butler, then, all of a sudden, he cuts out," Sweeney said.

"There are many compelling arguments for adding two judges for the western district . . . " Butler conceded in a statement, "but I cannot encourage it."

Both Harris and Butler agree that the huge western district, which covers the less populous western half of the state, has what Butler said seems to be a "tremendous" number of cases. In a presentation to the judiciary committee, Harris said that the number of cases filed in the federal court there has jumped from 791 in 1972 to 2,015 last year. The number of active judges - two - has remained the same, he said.

"This is an extremely heavy workload, which I believe justifies two new judges," Harris said.

Butler disagreed. He said 826 of the cases came from coal miners seeking black lung benefits under federal law and another 344 came from prisoners seeking new trials or release under federal law.

The way Butler sees it such cases can be assigned to federal magistrates, court officials who have less power than judges. When the black lung and prisoner petitions are removed, then the number of cases given the two active judges and the other additional new judge seems acceptable, Butler argued.

Federal judgeships are "conservatively" estimated to cost taxpayers $250,000 a year, Butler said. That's one reason they are so popular politically. A federal judge is paid $54,500 a year and is able to retire at age 65 on full pay after only 15 years service.

For the moment Butler's logic has held sway in the judiciary committee. it voted 21 to 13 against adding 33 judges back to its judgeships bill - a step that would have made Senate and House versions of the judgeship bill identical. Harris voted on the losing side.

The issue is far from dead. Sweeney, holds out hope that the committee might reconsider before reporting the full bill to the floor.

Butler himself has suggested he might reconsider when the bill is finally on the House floor or when House and Senate versions of the bill are in conference. What happens then might depend on how persuasive the lawyers in places like Abingdon, Big Stone Gap, Charlottesville, Danville, Harrisonburg, Lynchburg, and Roanoke are as lobbyists.

Even if Butler remains adamant and Harris fails, the vision of three judgeships will be enough to keep many Virginia lawyers angling for White House and Senate support in the coming months.