Many senators are simply angry at the long filibuster on the arcane subject of labor law revision, but not Orrin G. Hatch. He likes it.

Hatch, 44, a freshman Republican senator from Utah, is leading the filibustering forces, and he says he believes in the cause. This issue, he said in an interview, may be the pivotal fight in a struggle "to save this country."

To borrow from the senatorial phrase book, Orrin Hatch is tall, handsome, fiercely determined and deeply convinced. He is one of half a dozen younger, more stridently conservative newcomers who are working hard to make a mark on the Senate.

The tone of Hatch's general conversation can be heard in his commentary on the labor law debate thus far:

"I think we've torn 'em apart. That certainly isn't meant to be an arrogant statement. That statements is just telling the facts. I don't see how anybody could disagree with it."

Hatch was a trial attorney in Salt Lake City until his election 19 months ago. He held no previous political office, and decided to run for the Senate only two weeks before the filing deadline. He handily defeated Democrat Frank Moss, a liberal who had served three terms, and friends and colleagues say Hatch thinks he might run for something higher up the political escalator like the other end of Pennsylvania Avenue.

"I don't pay much attention to those comments," Hatch said in an interview near the Senate floor. "There are a lot of people who have encouraged me. But I just kind of laugh it off."

On the other hand: "If I ever felt strongly about running for a higher office, as I felt about running for the U.S. Senate, I'd do it." For now, the Senate is "the main battleground."

"He lives in a world of self'delusion," one Republican Senate source said of Hatch the other day. "He's impractical. He makes speeches to himself."

But the filibuster Hatch has succeeded beyond even his own preliminary dreams, and many well-placed supporters of the labor law revision bill now say they doubt it can get through the Senate. Its fate may be determined next Tuesday or Wednesday, when another attempt is made to persuade 60 senators to vote to cut off debate.

"There's nothing funny about Orrin Hatch," a lobbyist for the Carter administration suggested. "He's scary - really."

What scares Hatch is something different: "old, tired, worn-out ideas" and a "tyrannical majority" of Democrats and Republicans "who have dominated this country for 42 of the last 46 years and have put us where we are."

And where are we? In deep trouble, according to Hatch: "This country has been living in an excessive way for far too long. We have been unable or unwilling to solve our energy problems . . . We have allowed ourselves to enjoy materialistic growth to the extent that it means everything to us . . ."

The bureaucracy has become "an unauthorized, uncontemplated fourth branch of government," the dollar is in mortal peril, and the national debt. Hatch reckons, is "$6 trillion," including $2 trillion to $4 trillion in "unfunded Social Security debt," or future obligations for Social Security to workers who haven't retired.

Can a freshman Republican senator hope to do much to cope with this mess? Hatch says he is optimistic: "I see a number of younger senators who really, I think, put the country first . . . I do see a group emerging that may very well play a noble role in trying to help check some of the excesses of government."

Hatch leads two teams of six senators each in the labor bill filibuster. His staff has prepared towering piles of material for him to read in the debate, and Hatch seems to have mastered a pace of talking that is just fast enough to avoid accusations of stalling - but no faster.

The issue here is oppression of the private sector of the economy. Hatch argues, "I suspect if we add this one (the labor law bill) on top of all the other bad legislation that is one the books already oppressing America and oppressing businessmen across America, we're getting near the end where we can't do it any more."

(The labor law bill is intended to speed up and streamline certain federal procedures governing union organizing efforts. Organized labor says it would only make the existing system more efficient and equitable; opponents say the changes would lead to vast new unionization campaigns, inflation and interference in small business.)

Hatch hastens to note that he is a former union member, a lather who worked in the building trades for 10 years. "I'm darn proud of it, and I don't dislike the union movement," he said. "Without the labor movement we would have a rich and poor class in America, . . . The union movement has been responsible for the growth of the middle class . . . which I think has been very, very healthy."

Hatch argues that "The progressive legislation that is coming out of Congress today is coming from young conservatives . . . these are where the ideas are coming from today."

Offered a chance to impose his program in the Senate, Hatch said it would consist of three principal points: the tax bill originated by Rep. Jack Kemp (R.N.Y.) and now cosponsored by Hatch, which would reduce all federal tax rates by 30 percent: a new energy bill emphasizing new sources and price deregulation, and a stiffer national defense.

"Because this nation stands as abulwark to freedom all over the world . . . I would send a message to Russia that we are going to build the strongest deterrent force in the history of the world and that we will not let them continue this spiral. And if they want to play that game any farther we are going to stop them."

"Hatch's rhetoric has earned him, the nickname 'Borin' Orrin" in the halls of the Capitol, but his aides have told collegues they have actually toned the rhetoric down in recent months. "Remember," one said, "he was a trail lawyer."