While nobody was paying much attention, the Republican revolution of 1995-96 passed a crucial test in mid-July. The farm bill survived.

The farm bill was one of the signal reforms of the 104th Congress. It deregulated agriculture and began phasing out the price-support system that has been in place since the New Deal. Then this year, the farm economy went into a tailspin. A farm crisis in an election year should have given Democrats a clear opening to gut those changes, especially with Republicans fretting about losing control of the House.

But the Democrats didn't pounce. The implication is clear: If the farm bill can survive a crisis, maybe welfare reform--the other dramatic move by the GOP Congress to end a long-standing entitlement--will survive, too.

''The Farm Vote'' is one of the most fabled, and feared, institutions in American politics. ''Farmers should raise less corn and more hell,'' populist orator Mary Lease advised farmers 100 years ago. And they've been doing it ever since.

The rule is, farm politics follows farm prices. That has always made farmers the most volatile voters in the country. This year, farm prices are down. Way down. More than 30 percent down for staples like wheat, corn and soybeans. Why? You name it. A worldwide grain surplus. Bad weather. Crop diseases. And the financial crisis in Asia, which means Asians are buying less food from the United States.

As a result, farmers' anger is up. Way up. In the past, when farmers have raised hell, they've produced some of the most dramatic twists in American politics. Like Harry S. Truman's come-from-behind victory in 1948, which had a lot to do with discontent in the Farmbelt. And Democrats' recapture of the Senate in 1986, when hard times on the farm drove voters in North and South Dakota to dump incumbent Republicans.

This year's farm crisis has gotten lawmakers' attention. The Senate a few days ago passed a resolution, 99-0, that demands ''immediate action by the president and the Congress . . . to respond to the economic hardships'' facing farmers. Subsequently, however, the chamber turned back a Democratic proposal that would have liberalized the terms under which farmers could borrow money against their crops.

The 1996 farm bill ended a government program that was widely regarded as one of the most wasteful and expensive in American history. ''It represented the most comprehensive change in agricultural policy since the New Deal,'' Pat Roberts, R-Kan., said on the Senate floor earlier this month.

Farmers, once dependent on the federal government for survival, now depend on trade. So what happened? World prices collapsed. Sen. Byron L. Dorgan, D-N.D., described it this way: ''The farm bill was written by folks who said, 'Let's have the farmers operate in whatever the free-market system is.' Some of us said the problem is, there isn't a free market and, if farmers run into a price collapse, we are in a situation where they will not be able to get over the pricing valley.''

The Republican solution? More trade. Specifically, measures to lift the grain embargo against Pakistan, grant most- favored-nation trading status to China and help bail out Asian economies by providing emergency aid to the International Monetary Fund. And one more thing: fast-track authority for the president to negotiate trade agreements. ''If there was a single item important to higher income on the farm, it is that one,'' said Senate Agriculture Committee chairman Richard G. Lugar, R-Ind.

The Democrats' answer? More government assistance. ''I hope we will decide to embark upon a farm policy that says to family farmers, 'When prices collapse, and when you are ravaged by the worst crop disease of this century, we want to help you over those price valleys,' '' Dorgan said.

The debate sounds a lot like the debate over welfare reform. Farm-state Democrats claim reform threatens the safety net and the farm crisis proves it. ''The Freedom to Farm Act, in my view, is responsible in large measure for what has happened,'' said Senate Minority Leader Thomas A. Daschle, D-S.D.

Republicans insist the old system was a failure. ''Fifty years ago, we had almost seven million farmers in America,'' Lugar said. ''We now have two million. What kind of safety net lets that many producers slip through?''

As with welfare, there's not much support for going back to the old system. ''In this country, people have reached a threshold where subsidy payments and disaster payments are not popular,'' Lugar said. ''How could you justify such a naked
transfer of money from one group in society to another?'' The Democrats gave up--at least for now. ''These are emergency measures,'' Daschle said. ''We're not planning to re-open the farm bill.'' In the end, Democrats had to settle for $ 500 million in one-time emergency aid, plus a promise by Speaker Newt Gingrich, R-Ga., to accelerate the timetable for next year's farm subsidy payments.

But the big test may come on Election Day this fall. Democrats are counting on farmers to raise hell--and pull some major surprises. Incumbents who look unbeatable now may be in serious trouble come November. In the Farmbelt, the political weather can turn very quickly.