RICHMOND -- Senate Minority Leader William A. Truban (R-Shenandoah) gives new meaning to the phrase "loyal opposition."

A minirevolt on the Senate floor Monday produced one of the few victories of the legislative session for the minority Republicans, but it came without the help, and over the opposition, of Truban, who remained loyal to the Old Guard Democratic leadership.

"They didn't let me in on it," Truban said after the other nine Republicans in the Senate joined with dissident Democrats to pass a bill over the objections of the Democratic leadership.

Not that Truban would have cooperated had he been told of the planned coup. Truban apparently wasn't tipped off to the impending challenge to Democratic Majority Leader Hunter B. Andrews (D-Hampton) for fear he would try to dissaude some freshman Republicans from participating.

"It's not the way you legislate," Truban said of the tactic, which involved adding a floor amendment to an unreleated bill as a way of passing legislation that had been pigeonholed by the Senate Finance Committee. Andrews chairs that committee and Truban is its lone Republican member.

"You do it through the committee system," added the Woodstock veterinarian, now in his fifth term in the Democrat-dominated Senate.

While Truban carries the title of minority leader, Sen. Wiley F. Mitchell Jr. of Alexandria is the de facto GOP floor leader. Mitchell, who engineered the behind-the-scenes cooperation with back-bench Democrats, said, "The primary impetus {for the collaboration} was not legislation. It was to 'send a message.' "

The alliance demonstrated that "there is an alternative source of power" outside the Finance Committee, Mitchell said. "Properly inspired, or properly provoked," similar ad hoc alliances could surface again, he said.

Mitchell said he and other outsiders have "watched the rebuilding of the mystique that the Senate Finance is invulnerable, that we have to take whatever it serves, on whatever platter is offered."

That attitude was reality during the years in which the committee was chaired by Sen. Edward E. Willey (D-Richmond), who died in 1986 after 34 years in office, and many senators are determined that it won't occur again.

"It's important for the Finance Committee, and other members, to understand that {the committee} is the servant, not the master, of the Senate," Mitchell said.

Andrews appeared to take it personally, chastising several Republicans, including freshman Sen. Edwina P. Dalton of suburban Richmond, the widow of former Republican governor John Dalton, pointing out that her late husband opposed the principle for which she voted.

"I'm not basing my votes on John's views, although I am confident he'd be pleased," Dalton said later. "This was my first opportunity to vote for tax relief."

Insofar as the motivation wasn't entirely good government, the victory proclaimed by Lt. Gov. L. Douglas Wilder with the passage of the bill at issue also is somewhat diminished.

While both sides genuinely liked the product of their cooperation -- the legislaton combined Mitchell's idea of using lottery proceeds to provide a tax cut with Wilder's proposal to remove the sales tax on nonprescription drugs -- the overarching motivation was clearly political.

Both measures, in different forms, had been introduced separately, but shared a familiar fate: They were buried in a subcommittee of Senate Finance.

The compromise was put together by Mitchell and Sen. Dudley J. (Buzz) Emick Jr. (D-Botetourt), a prototypical outsider.

Because nearly every senator's motivation in the 24-to-15 vote was predicated on politics, one member on the winning side wondered aloud how the dissidents had managed to win the support of McLean Sen. Clive L. DuVal 2d, a member of the Democratic leadership.

"Could it be," the senator asked in mock amazement, "that Clive actually was voting his conscience?" (Like Mitchell and Wilder, DuVal had introduced legislation that would have provided tax relief this year.)

As for Truban, he has been rewarded for his go-along-to-get-along philosophy with the "Republican seat" on the Finance Committee. He is the only Republican so anointed, even though Senate rules say committee assignments "shall be composed . . . as nearly as practicable . . . in proportion" to their overall representation. Which in the case of a 15-member committee should mean three or four seats.