Fresh from an opening day caucus, where 35 new House Republicans had tried, but narrowly failed, to push their party into a hard-line stance against a convicted House member holding a chairmanship, a senior Republican sighed and said, "Oh boy, I guess it's our turn now."

Since 1974, when 77 new Democrats came to the House and immediately unseated three senior chairmen, Democrats three senior chairmen, Democrats have become accustomed to freshman members who want to be both seen and heard.

In fact, the cohesiveness of the '74 class, its outspoken demands for participation and its independence from its party and House leadership has led to the cliche that Congress is a very different, very hard to govern place.

In the intervening years, new Republicans were few number, and tended to melt into the minority party, leaving hardly a trace.

This year seems to be different.

By the end of the first week of the new Congress, the 35 new Republicans had formed a freshman caucus and had passed several resolutions.

One called upon the Judiciary Committee to start work on a constitutional amendment to balance the budget. Another asked Republican hopefuls for the 1980 presidential nomination to meet with the freshmen.

The freshmen also initiated a letter of complaint to the Committee on Standards of Official Conduct, asking that it look into grounds for expelling convicted Rep. Charles C. Diggs Jr. (D-Mich.).

Unilke the '74 Democrats, the new Republicans are not as numerous and cannot be expected to have as great an impact on the House or even their party.

But, like the '74 Democrats, they have come to Congress with strong feelings that they were chosen by the people to make things happen.

The '74 Democrats were a post-Watergate class who felt their mission was to clean up government and make it responsive.

The '78 Republicans are the post-Proposition 13 class and feel their mandate is to slow down inflation by cutting spending and balancing the budget.

"I didn't come here to warm a seat," said Rep. James Sensenbrenner, a freshman Republican from Wisconsin.

Unlike the '74 Democrats, the new Republicans have not directly taken on their leadership -- not yet. But, as Rep. Tom Tauke (R-Iowa) said in the first meeting of the freshman class, "I came to Congress not just to shake up the Democratic majority, but to shake up the minority."

One of the first breaks with the leadership may come over a constitutional amendment to balance the budget. House Minority Leader John J. Rhodes (R-Ariz.), conference chairman John B. Anderson (R-Ill.), and Rep. Barber B. Conable Jr. (R-N.Y.), the ranking minority member on Ways and Means, are opposed to the idea of a constitutional amendment, and would prefer balancing the budget through the normal legislative process on the budget resolution.

"I think the established leadership in Washington really isn't reading where the people are coming from," said freshman Rep. Jerry Lewis (R-Calif.). Lewis said he opposed Proposition 13 when he was in the California Legislature. But after it passed he watched the leadership, which had said for 10 years that certain cuts in the budget couldn't be made, make $1.3 billion worth of cuts "in five hours." "It's a mind set they get into about what can and can't be done," Lewis said.

The president of the Republican freshmen is Rep. Ed Bethune (R-Ark.), a thoughtful man and a former FBI agent, who pulled one of the last election's biggest upsets to become the first Republican in 104 years to represent Wilbur Mills' old district.

Bethune agrees about the mind set, and he sees the freshman class as the formulators of a new populism who could help lead the Republican Party out of its doldrums.

Bethune said what brought this class together in the first place was that "we broke out of the stereotyped Republican mold. We ran a grassroots campaign, sometimes apart from our party. We think we have a lot to offer in formulating a winning strategy and we think we know quite a lot about how the electorate feels.

"For too long Republicans have been tagged as friends of big business, politicians who don't care about people. My own campaign was the antithesis of that. I was anti-establishment. I let people know of my willingness to stop wasteful spending, get control of government and clean up institutions, but most of all, I let them know I was willing to listen to them."

Lewis said, "if we really care about old people and the unemployed, then attacking inflation is the place to begin. Having a lid on spending, then giving some priorities, that's the new populism."

Bethune said the class wanted to talk to GOP hopefuls to tell them that the Republican Party must be "willing to run the risk of new ideas. We have to get that message across, to get them to incorporate the freshness we felt in their campaign, even if they are old faces.

Rhodes calle the freshmen "all fired up," and said he welcomed them. "It's much easier to channel enthusiasm in the right direction than it is to generate it."

But whether he can channel their enthusiasm for a balanced budget constitutitonal amendment into the direction he wants to take or whether he will be overtaken by it and swept along is not clear.

And whether 35 Republican freshmen can have an impact on legislation is not clear. "It's amazing what you can do if you don't care who gets credit for it," Lewis said, brushing aside the fact that they are less than one third of House Republicans. "We could be of assistance to the majority." Lewis said he thought the Democratic freshman class campaigned on the same themes as Republican freshmen and that a coalition might be formed.

"We could have the seeds of a new majority," Lewis said.