On one level it is an almost classic "Mr. Smith Goes to Washington" story, starring an unsophisticated insurance salesman who comes to the capital to do battle for the little guy.

Seen this way, Rep. George V. Hansen is like a tall and lonesome pine, a 6-foot-6-inch westerner honed into a super-conservative mold by the isolation of southern Idaho's high plateaus, who came to the House determined to take on all those Big Brother laws and regulations that so irritate his neighbors back home.

The only problem with this is Hansen: his story has more twists than an Idaho logging road.

The Republican congressman was hardly off the plane from Pocatello in 1975 before he was in the thick of battle. Unfortunately, the first little guy Hansen found himself defending against those pesky federal laws was himself.

Three months after he took office, Hansen pleaded guilty to two violations of the post-Watergate campaign-reform laws. The judge threw the book at him, telling the congressman that the laws were written for politicians and the little guys alike.

Hansen was sentenced to two months in jail. His wife cried. He said the conviction proved his campaign point: that government's "excessive and oppressive laws threaten us all." His lawyer finally kept him out of jail with a most unusual defense: he told the judge Hansen was "stupid, but not evil."

If that was not a particularly auspicious debut, Hansen was undeterred.

Like a latter-day Don Quixote, his lance sharpened for bureaucrats and big spenders, Hansen galloped chaotically off in search of targets that ranged from the Internal Revenue Service to the federal abortionists.

He also made some unusual overseas trips. He also fell deeply in debt. And last month the George Hansen story seemed to come full circle with disclosure that federal prosecutors were investigating his activities again.

When Hansen arrived here after the 1974 elections he was beginning his second congressional stint. He had spent two terms in the House in the mid-1960s, every bit the conservative that he remains today, but young and overwhelmed by the heyday of LBJ's Great Society. In four years here he came and left almost unnoticed.

In 1968 he returned to Idaho and made the first of two runs at the Senate, losing in both. Then, in 1974, he ran for his old House seat, ousting a Republican incumbent named Hansen and then defeating a Democrat named Hanson.

Some onlookers said that confusion reigned in Idaho over all this, but George V. Hansen arrived here again in time for his trial. He never went unnoticed again; he was like a loose cannon on the decks of the House of Representatives, one of his Republican colleagues observed.

He fought the Internal Revenue Service, charging that the IRS was planning armed raids on homes in Idaho Falls. He fought the Immigration and Naturalizaton Service, charging that the feds brought in illegal Mexican workers, entrapped his Idaho farmers into hiring them and then arrested the farmers. He spent three years helping a Pocatello businessman battle the Occupational Safety and Health Administration all the way to victory in the Supreme Court.

He rode all the conservative issues, threatening President Carter with impeachment proceedings over the Iranian hostage issue, fighting the Panama Canal treaties and assaulting federal abortion laws.

"Stop the Baby Killers," screamed an Americans for Life fund-raising letter aimed at defeating liberal senators and listing George Hansen as co-chairman. One of the targets was Idaho's Sen. Frank Church, to whom Hansen had lost in his first race for the Senate. Hansen said he didn't write the letter's text, but "when people get emotional they can get pretty graphic and still be accurate."

But Hansen was finding his fight against big government to be unusually expensive. It cost money, he said, to live down his "stupid-but-not-evil" debut. It cost money to "protect myself" against the enemies a man makes protecting the little guy. He also made a lot of unusual trips.

By 1977, he acknowledged that he was deeply in debt. He asked the Federal Election Commission if it was legal to solicit funds to pay off his personal obligations. In his letter to the FEC, Hansen noted that congressmen have "the same needs for financial security" as do other folks.

The FEC said the fund-raising was legal. The House Ethics Committee, however, said the unusual plan would violate House rules.

Six months later, Hansen found a way around those annoying rules. Under Idaho community-property laws, the Hansens split their belongings. In effect, the congressman took the assets and his wife, Connie, took the debts.

Hansen said the debts came from a "sustained political assault" by his opponents. His wife sent out the Connie Hansen Fund direct-mail appeal, saying that she needed "hundreds of thousands of dollars" to "save my family from financial disaster." No public accounting ever was made of the proceeds.

Hansen's congressional office is Capitol Hill-conventional, full of the usual photographs and Idaho artifacts. A few back-home oil paintings depict wintry scenes of the remote highlands that lead up to the Bitterroot Mountains.

Connie Hansen, blonde and smiling that strained political-wife smile, sits daily by her husband's office door. She works as an unpaid assistant, even though they could use the money. Hansen's 1981 public-disclosure forms and other records showed the couple still owed at least $300,000 to nine banks.

Hansen doesn't like to talk much about his financial situation, especially to reporters. He says that he has been the victim of "head hunters" and "a very aggressive group of people in the press." He also says he has been "caught in a political power struggle," although he is vague about who is on the other side.

"I always try to play by the rules," Hansen says, swiveling his 250-pound bulk around to smile out of the big chair behind his congressman's desk. "This life gets expensive.

"How many congressmen do you know who get on a plane and fly to South America to get one of their constituents out of a dung heap of a prison in downtown Bolivia sic ?" he asks. "And takes his wife into that kind of environment?" He pauses. "My wife said the only way we're going to get him out is go there," he adds, then returns to the financial problem: "I got caught in a power struggle. I had to hire lawyers and accountants."

The big travel year was 1979. That was the year he flew to Tehran to work on the hostage crisis. He got in to see the hostages, when official representatives could not. He also promised the Iranians an investigation of the shah.

The vision of a Quixotic congressman from Idaho floating around Tehran, negotiating with the Iranians and talking to the hostages when even the president's emissary couldn't get in caused the Carter administration to turn purple. The administration called the trip irresponsible in public and worse in private. The speaker of the House, Thomas P. (Tip) O'Neill Jr. (D-Mass.), declared that Hansen had "very little credibility" on the hostage issue or anything else.

In 1979, Hansen also flew to Nicaragua. While there, he assured President Anastasio Somoza that the United States remained solidly behind him. The problem, Hansen told the Nicaraguan dictator, was that American journalists had lied and "distorted" the Somoza story. Two weeks later Somoza was overthrown.

Late in the year Hansen went to Taiwan. He told Taiwanese leaders they had friends in the United States, despite improved U.S. relations with the mainland. He also promised them that they would get "the final equipment necessary to complete the atomic program you have started."

He made two other high-flying trips in 1979. On the first he was clocked at 81 mph, but the policeman let him go when he claimed congressional immunity. On the second, he was clocked at 79 mph. The policeman listened to the congressional-immunity story, but ticketed him anyway.

"I take strong stands," Hansen says with a quiet, Jimmy Stewart smile to match his "Mr. Hansen Goes to Washington" self-image. "Anybody active and aggressive is going to cause waves. You learn how to protect yourself." What bothers him most, he says, is that "a lot of people just can't believe" that he has been "totally committed" to public service.

At times, Hansen has trouble deciding which flank to protect. "I've been on every hit list there is," he says. "One year I was on seven hit lists and was the dirtiest of the dirty dozen," a list of congressmen who vote poorly, in the eyes of environmentalists.

Still, he understands those adversaries--natural antagonists for a man who is against big government and for the little guy. His visage turns more stern when asked about the latest episode in the George Hansen story.

In December, almost eight years after his federal-court debut here, The Wall Street Journal reported that federal prosecutors are investigating Hansen for allegedly borrowing $135,000 from a convicted Virginia bank swindler. Hansen is a member of the House Banking, Finance and Urban Affairs Committee.

Hansen had failed to report the loan under another of those irritating federal laws: the Ethics in Government Act. He says that he borrowed the money to support his help-the-little-guy campaign against the Internal Revenue Service, not to support himself, and therefore was not required to file a report. The money, he said, went to a group he formed two years ago called the Association of Concerned Taxpayers, and to promote his book, "How the IRS Seizes Your Dollars and How to Fight Back."

Investigators also have been looking into a $50,000 loan that Hansen's wife received from Texas billionaire Nelson Bunker Hunt. That loan also went unreported on the disclosure forms. Additionally, the investigators are probing an $87,000 profit Connie Hansen allegedly made in a three-day speculation in silver futures in 1979, while Hunt was trying to gain a corner on the silver market.

In 1979 Hunt also was involved in intensive, and successful, negotiations to gain control of the famous Sunshine silver mine in Idaho. In 1982, after Hunt's efforts to control the silver market collapsed, the Texas billionaire closed the mine, throwing a lot of little guys out of work in Hansen's home state.

Hansen has avoided direct comment on what he calls the "stew of innuendo in the Wall Street paper." He says he has been investigating a "multibillion-dollar swindle" by investment bankers in a public-power scandal in the Northwest.

"Should anyone have any doubts," Hansen asks, "why Dow Jones owner of the Journal and the New York financial community wants a building to fall on me?"

Rocking back in the big chair in his congressional office, Hansen hints darkly that his fight for the little man now has brought more than the wrath of big government down on his hulking shoulders.

His latest problems have to do with "big financial interests," he says, and "the impending collapse of the international banking system." He says that "they know" he is investigating. But who are they? "I don't know who they are," Hansen answers, with a woe-begotten look. "I just ask the question back to you."

Hansen says that his trip to Iran proved to him that the big financial interests were behind the hostage crisis. After his visit to Iran, Hansen says, he appeared on a television talk show "and said Henry Kissinger and David Rockefeller ought to be sitting there instead of the hostages, because it's a banking matter." After the show, Hansen says with a knowing look, the talk-show host warned him that he wouldn't receive many more television invitations if he continued to talk that way.

Hansen says he also has concluded that the "big financial interests" were behind the Panama Canal treaties and are handcuffing the United States in its dealings on the Polish crisis.

"I just ask you: Who got their money first at the conclusion of the hostage crisis ?" he says. "The bankers," he answers his own question.

"When a lonely congressman takes on big vested interests like that," Hansen adds, "maybe he steps on some tender toes."

Hansen last year also took on the Immigration Reform and Control Act that failed of passage in the final days of the lame-duck Congress. He says that he is deeply concerned about "the alarming swarm of aliens invading America's borders." But he is more worried about the bureaucrats in the Immigration and Naturalization Service.

Hansen wrote a letter to his House colleagues urging them to defeat the bill, which he says gives INS agents "more authority to harass employers, violate the most elemental rights of human beings and continue their now notorious methods of entrapment, brutality and even murder."

No one, friend or foe, has ever faulted Hansen for not trying. But his INS campaign, even with charges of murder by government agents, has turned fewer heads than has The Wall Street Journal.

"We would welcome the crowd," says Hansen's press aide, James McKenna, "if they weren't here for the hanging."

Hansen, for his part, insists that he really would like to know who it is who is out to stop "a lonely congressman" from a far-off state.

"When you find out who they are," he says with a wistful smile, "let me know." In the meantime, he says, "I still have some work to do." He pauses. "I see a country in serious trouble." He pauses. "Really deep trouble."

Then George Hansen stands up like a tall and lonesome Western pine that refuses to bend to those cold winter winds that whistle out of the Bitterroots.

"Let 'em talk," he says. "I know who I am." He pauses. "I grew up saying, 'Sticks and stones . . . . '