A decade after Congress voted to open all committee sessions to the public in the interests of "government in the sunshine," some of its most important committees have started closing legislative voting sessions, saying they can get more done behind closed doors.

Most committees still hold open legislative sessions, but important exceptions are occurring. Just before the current summer recess, the House Ways and Means Committee met in closed session for two full days to vote on dozens of provisions of a $19 billion three-year deficit-reduction package.

Under House rules, to close a session a committee must meet publicly and vote whether to exclude the public and media. As Ways and Means was doing so -- one day by a 20-to-1 vote -- Chairman Dan Rostenkowski (D-Ill.) remarked matter-of-factly that the committee had been closing some similar meetings for several years.

On July 30, the House Energy and Commerce subcommittee on health and the environment, which usually does business openly, held a closed "caucus" to discuss health budget matters.

Although no formal actions were taken, Rep. Thomas J. Bliley Jr. (R-Va.) said later at an open voting meeting of the full committee that the "caucus" had agreed to accept the committee's health provisions.

The House Budget Committee closed its doors May 15-16 to try drafting a budget.

When Senate-House budget conferees later agreed on a compromise, most of it was arranged in closed meetings involving the Senate Budget Committee's chairman, Pete V. Domenici (R-N.M.), and senior Democrat Lawton Chiles (Fla.), and the House Budget Committee's chairman, William H. Gray III (D-Pa.), and senior Republican Delbert L. Latta (Ohio).

Then, the pact was sent to the open House-Senate conference committee for final touches and ratification.

Such closed sessions are held because members have expressed the feeling that they can arrange compromises more easily when lobbyists cannot watch their every move and every decision does not have to recorded formally.

"I think you have more candid exchange. You don't have a lot of posturing and efforts at political tradeoffs that you do when forced to make decisions in front of vested interests," said John Salmon, former chief counsel to Ways and Means and now a lawyer in private practice here.

Closed sessions also preclude a tendency to perform for television. Outside the budget conference room, staff members and reporters said jokingly of one member: "He had a brain transplant, and a monitor was put in so that every time a TV camera goes on he shows up in the room."

Before 1973, most committee hearings were public, but 80 percent of meetings to amend and vote on legislation were closed, according to a 1972 House survey by Congressional Quarterly.

Such organizations as Common Cause, the League of Women Voters, the National Committee for an Effective Congress and the United Auto Workers began a campaign to open these so-called "markup" sessions, arguing that the public was entitled to know what deals were struck and who pushed for what.

Chiles and Sen. William V. Roth (R-Del.) had long pressed for "sunshine" rules. John Pastore (D-R.I.) told the Senate that the basic argument for opening markup meetings was that people held Congress in low esteem because they thought it had something to hide.

In 1973, the House adopted the open-markup rule, but the Senate rejected one for itself, 47 to 38. Russell B. Long (D-La.) maintained that closed meetings "reduce the power of an organized group to try to stampede the committee."

Two years later, however, in the era of "post-Watergate reform," the Senate voted, 86 to 0, to require open markup sessions unless the committee voted for closed meetings to protect national security, internal staff information, trade secrets, identities of undercover law officers or other matters requiring confidentiality. Also in 1975, both chambers voted for open sessions of House-Senate legislative conference committees.

The new "sunshine" rules brought remarkable changes to House and Senate. Except for committee sessions dealing with a few national-security issues, most meetings were opened, and most markup sessions still are.

But the countertrend has begun.

For example, the House Appropriations subcommittee handling the largest domestic budget -- Labor, Health and Human Services, and Education -- has been making decisions in closed session since 1979, when Rep. William H. Natcher (D-Ky.) became chairman.

Ways and Means, after several years of open sessions under former chairman Al Ullman (D-Ore.), closed its 1980 markup on the reconciliation bill. Under Rostenkowski, it also closed sessions of its 1982 tax markup, and 1983, 1984 and 1985 deficit-reduction and tax markups.

A partial survey of committees found that several subcommittees of House Foreign Affairs sometimes meet in closed session. At the House Appropriations Committee, so do the subcommittees on defense, HUD and independent agencies, foreign operations and energy and water development, according to committee aides.

The House Armed Services Committee also held many closed sessions.

In the Senate, most committees hold open sessions, but the Armed Services Committee and the Appropriations subcommittee on defense often hold closed sessions. The Commerce, Science and Transportation Committee has held closed meetings on space issues, and the Foreign Relations and Judiciary committees have done so on some security matters.

Even on nonsecurity matters, some Senate committees, such as Finance, have basically worked out many issues in recent years in closed caucuses or informal meetings and then more or less ratified the understandings at open meetings; whether this violates the spirit of the sunshine rules is unclear.

Ann McBride, senior vice president of Common Cause, does not like the trend toward more secret meetings.

"It's a sad thing when elected officials feel they have to hide behind closed doors to make decisions. The special interests find out anyhow how people voted. It's the public that loses out. The public's right to know still is fundamental and should override these other considerations," she said.