For three elections, the cutting issues, the mood of the voters and the disarray of the Democrats have all worked to the benefit of Rep. Arlan Stangeland (R-Minn.).

One of the early victories for the then-emerging New Right, Stangeland won his 7th District seat in a 1977 special election, capitalizing on the sudden collapse of the state's Democratic-Farmer-Labor party and a weak opponent who was neither a farmer nor a Scandanavian.

Since then, his margin of victory has steadily declined. In both 1978 and 1980 he defeated Gene Wenstrom, who is both a farmer and a Scandanavian, with the help of the conservative-Reagan tide and deep farmer antipathy to Jimmy Carter, who had banned grain shipments to Russia. In 1978 he beat Wenstrom by 54 percent to 46 percent, two years ago it was 52 to 48 percent.

Now, as he faces Wenstrom a third time, the tenor of the campaign has shifted. Stangeland has to defend his party's farm policy when crops are selling for less than the cost of production, dairy price supports will drop the month after the election, and only hogs produce a profit.

In addition, Minnesota farmers voice a deep anger. They see themselves as a central part of the nation's economy, not only providing food but going deep in debt to buy $18,000 tractors,$75,000 combines and $12,000 trucks that provide jobs to industrial America, while the rest of the country lets farmers move closer to backruptcy.

"The farms are not where the nation's problems arise," contends Cy Carpenter, president of the Minnesota Farmers Union. "That's where they come to rest. The rural and agricultural community are declining faster than any other segment of the economy."

Facing a panel of county newspaper editors here at the first confrontation between the two candidates, Stangeland moved back and forth from forthright support of Reaganomics and optimistic projections for the future to defensive explanations of past votes.

Asked why he voted to give the administration authority to reduce dairy price supports, Stangeland replied: "I voted for it for the simple reason that this came out of the conference committee" -- that is, it was part of a larger spending reduction bill and House rules did not allow dissents on specifics. "I don't agree with the dairy reduction."

At one point, Stangeland declared his strong support of the president.

"In 1980, there was a clear-cut vote, President Reagan outlined very clearly what directions government will go. More than most politicians, he has kept his promises."

But later, he was careful to stress that he is no Reagan robot, noting dissents on farm bills and administration proposals to cut student grants and loans.

Republican anxieties are also revealed in the negative ads of Rep. Vin Weber who has the advantages of incumbency and a nearly 4-to-1 edge in money. One warns: "Farmers beware of hazardous waste, the DNR Department of Natural Resources and Jim Nichols," his opponent in the 6th District.

Minnesota is a testing ground not only for Reaganomics, but for the Democratic-Farmer-Labor party, which is struggling to regain its elective muscle. It was a bedrock of the Roosevelt-Democratic coalition that dominated the state until the 1978 "Minnesota Massacre," when Republicans won the governorship and both senate seats.

Any DFL recovery won't be easy.

Against Weber, Nichols has a money shortage characteristic of many Democratic challengers. He has raised $82,000 compared to Weber's campaign fund in excess of $300,000.

Wenstrom, by contrast, is an unusual political commodity this year: a relatively well-financed Democratic challenger. With the state and national Democratic parties, along with organized labor, sensing a chance for victory, Wenstrom has raised a respectable $190,000 to Stangeland's $244,000.