After two years of partisan and highly publicized confrontations, a strange kind of quiet has descended on the usually noisy band of young Republican conservatives in the House who are charter members of the Conservative Opportunity Society.

The legislative guerrilla tactics that first brought them to prominence -- the long partisan speeches pitched to the television cameras that record House sessions, the baiting of Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) and other Democratic leaders, the parliamentary maneuvering that often tied the House in knots -- have all but disappeared from the House floor during most of this year.

Names and faces that became as familiar as soap-opera characters to the House's relatively small but devoted television audience are no longer playing their roles in the daily legislative drama. House members speak of the COS and its spiritual and intellectual leader, Rep. Newt Gingrich (R-Ga.), as having "gone underground."

Has the conservative revolution in the House come and gone so soon?

Many Democrats, and some Republicans, say that they hope so. Guerrilla tactics may make for entertaining theater, but they are the antithesis of the House's cherished traditions of courtesy and decorum. At its peak, in 1983 and 1984, the COS sometimes managed to irritate the established Republican House leadership and often outraged the Democrats.

But Gingrich says those who hope for a permanent return to business as usual on the House floor are doomed to disappointment. He describes the last several months as a period of "reassessment" and "consolidation," and of plotting strategy for the next round of clashes.

"We have won round one," he said. "We are now a national movement."

That they are at least a force to be reckoned with is acknowledged even by Rep. Tony Coelho (D-Calif.), chairman of the Democratic Congressional Campaign Committee and the frequent point man on the other side of partisan legislative battles.

"They provided some intellectual stimulation to the Republicans," Coelho said. "Traditionally, Republicans just laid back and let us do it to them. These guys changed that, but they went too far."

In the beginning, there were fewer than 10 of them in the House, distinctly junior Republicans who were inspired by the conservative rhetoric and ideas of Gingrich, a former college professor who was first elected to Congress in 1978. Gingrich coined the phrase "Conservative Opportunity Society" -- meant as a contrast to "Liberal Welfare State" -- and around the philosophy embodied by that slogan, the COS was formed in 1982.

Noisy, disruptive and deliberately confrontational, the COS attracted a disproportionate amount of attention in the news media, which is exactly what it sought. Last year the conservative Republicans goaded O'Neill off the speaker's podium and onto the House floor, where some of his remarks during a rhetorical assault on the COS were ruled out of order.

By the time of the 1984 Republican National Convention in Dallas, many of Gingrich's ideas had found their way into the Republican platform and President Reagan was referring to the GOP as the "Grand Opportunity Party."

They were riding high, and more of the same was expected when the 99th Congress convened last January. But with the exception of the long and bitter clash over a disputed House seat in Indiana -- a fight in which the COS played a leading but by no means the only important role on the Republican side -- 1985 has been nothing like the two previous years.

There is no shortage of people on Capitol Hill willing to claim credit for helping to shut up the COS. Democrats like to point to a brief statement on the House floor in April by Rep. Andrew Jacobs Jr. (D-Ind.), who offered a definition of the term "war wimp" as "one who is all too willing to send others to war but never gets around to going to war himself." Jacobs didn't name names, but he was clearly talking about Gingrich, Rep. Vin Weber (R-Minn.), the COS chairman, and several others among the young conservatives who advocate the use of military force to combat Soviet expansionism but who never served in the military.

" 'War wimps' shut them up faster than anything," a Democratic staff aide said gleefully.

Gingrich shrugged off the "war wimps" charge, saying that there were a variety of reasons he and some of the others never served in the military during the Vietnam era, including physical health and family status. "I expect those on the left who don't like me to attack me," Gingrich said.

Moderate House Republicans also claim a share of the credit. Last December, a group of moderates formed the "92 Group," with the goal of achieving a Republican House majority by 1992. While what COS has done is "fine," said Rep. Thomas J. Tauke (R-Iowa), the 92 Group chairman, the moderates felt compelled to "provide a broader perspective of the Republican Party in the House."

"We are not as silent a group as we were," he said. "They have to share the spotlight with us."

Weber, the COS chairman, agrees that the group has toned down its rhetoric and lowered its visibility, but for reasons having nothing to do with Democratic jabs about "war wimps" or the emergence of an organized force of Republican moderates in the House.

Part of it is a natural process, cited by others in the House, in which fiery young newcomers hellbent to make a difference in Washington are gradually drawn into the more mundane tasks of lawmaking.

In the early days, Rep. Connie Mack III (R-Fla.) of COS once promised to produce his version of a balanced budget for the federal government in 30 days. He found that was easier said than done but now he has risen to the middle level of seniority on the Republican side of the House Budget Committee and is deeply engaged in real budget-making.

In addition to this predictable phenomenon, Weber said, the COS has been busy absorbing and training new members from among this year's Republican freshmen and has channeled some of its energy into activities away from the House floor, including the formation of a COS political action committee.

Finally, there is the role of Gingrich, which is central to the fortunes of the organization he inspired. While Weber is the COS chairman, Gingrich remains the chief strategist and real leader. "COS is not separable from Newt Gingrich," said Eddie Mahe, a Republican political consultant and unofficial adviser to Gingrich and COS.

By all accounts, this has not been a good year for Gingrich. Never known as a master of personal relationships, Gingrich, according to associates, alienated even many of his friends with an increasingly overbearing manner. Puffed up by the successes of 1984, he once told a group of friends that he and Weber were "the two most powerful people" in Washington.

It was more than many of his friends could take, and they told him so. Gingrich withdrew, becoming what some called "almost a recluse" by this spring. In the meantime, the freewheeling, Democratic-baiting COS seemed to lose much of its energy if not its sense of direction.

Gingrich does not deny any of this. He said he has been going through "an enormous reassessment" of his role as the COS leader while trying to map a new conservative strategy for the coming years.

"I think we have to work harder to focus on issues rather than personalities," he said. "It requires more systematic thought and planning. This is the inevitable cost of success -- the freewheeling style of the freshman is too abrasive when there is as large a megaphone in front of you as there is now."

If this suggests that COS will continue to rely less on the legislative guerrilla tactics that first put it on the political map, Gingrich and Weber insist it implies no lessening in the young conservatives' devotion to their cause. Next year, after all, is an election year, a time for more partisan tactics, they noted.

Gingrich, meanwhile, is showing signs he is about to return to the battleground, which is what several impatient COS members asked him to do during the August recess. Thursday he was back at the House podium -- speaking to the television cameras rather than the nearly empty chamber -- about his latest pet project, to turn next month's anniversary of the U.S. invasion of Grenada into an annual observance on the evils of communism.

He says he is also thinking a great deal about the political implications of the spread of the AIDS virus, suggesting a likely future clash between the "community values" he says COS stands for and "ideological, left-wing" notions about privacy and discrimination.

"I've said over and over again that this is a long-term effort," Gingrich said. "I'm very comfortable in not having our group trying to dominate through the entire 24-month cycle of a Congress. I don't think it's possible."