The state that gave the nation effusive Hubert Humphrey, quixotic Eugene McCarthy and earnest Walter Mondale has come up with a hot new political commodity. He's a 49-year-old dentist with the unlikely Minnesota name of Rudy Perpich.

In a place where governors almost invariably are blue-eyed Scandinavians and senators routinely think of themselves as presidential timber, Perpich is an oddity.

He is dark. He is Catholic. And he says he has no national ambitions. In fact, he has yet to move his family from his home in Hibbing to the governor's mansion. "The difference between me and those other guys," he declares, "is I'm going home when it's all over and I don't think my family will shed a tear."

In his seven months as governor, Perpich has been unpredictable, open almost to a fault, and, at times, outrageous.

At various points, he's banned the pickup of litter along state highways, ordered that a $17,500 increase in his salary be used to buy Italian bocce balls, thrown away a prepared speech when he found the crowd would rather see him polka, dined with Minneapolis' best-known madam, and slipped away from his office alone and unannounced to mingle with farmers and small town businessmen.

He's been called "Crazy Rudy," the "Lone Ranger," and the "disappearing governor" for his antics. But his unorthodox style and his record of dealing with a series of ticklish issues have left him in an unusually strong political position for a man unknown to many state voters when he was appointed to office last December.

Whetehr he can maintain that standing when he runs for election on his own next year is a matter of great conjecture. "Minnesotans may find that what looks exciting today is likely to turn out to be a lack of substance," says Rep. Bill Frenzel (R-Minn.) who served in the state legislature with Perpich.

But few Republicans deny that Perpich is riding a crest of popularity, or that he has added a new dimension to Minnesota politics. "I don't give him good marks as governor, but I do give him credit for putting fun into politics in the state," says Chuck Stocum, former state Independent Republican chairman.

There's a touch of the new politics of Georgian Jimmy Carter and Californian Jerry Brown in Perpich. He travels coach and carriers his own suitcase. He avoids national meetings of governors, has set up a task force to find waste in government and claims one of the best ways to make government more efficient is to keep bureaucrats from buying any more filing cabinets.

But his style is strictly Midwestern. It is Main Street populism, a combination of smalltown naivete and openness, sprinkled with an affinity for the underdog.

He spends days visiting county fairs and shopping centers, getting what he claims is a cross-section of public opinion. He plunges impulsively into issues some politicians wouldn't touch.

When a controversy developed over a stop light in an American Indian neighborhood in Minneapolis, Perich visited the site, met with community leaders and pushed for a light, although it was a local, not a state issue. When tensions over a controversial powerline in central Minnesota flared to a fever pitch last winter, he slipped quietly out of his office and spent the next two days visiting farmers upset over the utility line.

"You have to be out there talking to people to know what's going on." Perpich declares. "Something that might sound like a Mickey Mouse issue to big shots in Minneapolis may mean the world to someone else. So I just take off and go."

That Perpich is governor at all is an accident of history. Jimmy Carter set it in motion when he picked Walter Mondale as his running mate. When Carter was elected, Gov. Wendell Anderson appointed himself to fill the Senate seat Mondale vacated, Lt. Gov. Perpich became governor. He could barely conceal his glee. "I'm proud to be the governor and I'm not going to be hangdog about how I got there," he told one reporter.

Perpich readily concedes he probably never would have been elected governor in his own right.That office has long been the special preserve of Scandinavian Lutherans with names like Anderson, Olson, Peterson, and Youngdahl.

Perpich is the first Minnesota governor who is a Roman Catholic. He's also the first from the state's Mesabi Iron Range in the northeastern part of the state, a fact that shaped his personality and politics.

The oldest son of a Croatian immigrant iron ore miner, he grew up poor, hating the steel companies that dominated the area. He entered school without knowing English or the fine points of indoor plumbing. When he heard a toilet flush on his first visit to the school restroom, he was horrified and ran home, informing his mother that a water pipe had burst. "I told her 'I got out but I'm not sure if the rest of the kids made it or not,'" he recalls.

Anton Perpich didn't want his sons to work in the mines. He saw education as the way out. Rudy and two of his brothers became dentists, then state legislators. The fourth brother became a lawyer and psychiatrist.

As lieutenant governor, Perpich lived in Anderson's shadow and suffered by comparison. Anderson was well-organized and predictable, Perpich was the opposite. While Anderson, a former All-American hockey player, looked handsome on television, Perpich's rugged features invited caricature. While Anderson was dignified and well-liked by Domocratic Farmer Labor Party regulars, Perpich, a poor orator, was unpretentious and suspect.

But to almost everyone's surprise he quickly captured the public imagination after becoming governor, and by midspring a poll by the Minneapolis Tribune reported 63 per cent of those surveyed felt Perpich was doing a good-to-excellent job while only 4 per cent gave him a poor rating.

His off-the-wall antics such as a decision to promote participatory sports by donating his salary increase to buy bocceballs (for an Italian lawn bowling game popular on the Iron Range) attracted widespread attention.

More important, Perpich created the impression - whether real or imagined - that he was dealing head-on withe the state's three most controversial issues; A new stadium for the Minnesota Vikings and Twins (he appointed a blue-ribbon site selection committee); the power line controversy; and a long-fought battle over Reserve Mining Co.'s dumping of taconite waste into Lake Superior (he expedited moves to set up a new inland disposal site opposed by environmentalists).

Perpich is not without his critics. He has angered labor leaders with several appointments, made some party leaders uneasy over his shoot-from-the-hip manner and worried his friends over his failure to delegate authority. Republicans charge he really hasn't accomplished anything in office. "The problem with Rudy is that he's out of control," says Congressman Frenzel.

And there is the possibility that his "just plain folks" image may wear thin.The St. Paul Dispatch, for instance, recently called him "Mortimer Snerd" after Perpich had trouble getting into a meeting with President Carter because he had no identification to show White House guards. Perpich's explanation to reporters was: "Why should I carry a wallet? Everyone knows me back home on the range."