BLOCKING HIGHWAYS as a method of political protest is intolerable. But these farmers are pursuing a goal that is even more wrongheaded. They want a massive price increase that would severely hurt consumers and send the inflations rate shooting upward. THe farmers' distress is real, but they are rapidly squandering public sympathy. Their attemps to block roads are symbolic - more, prehaps, than they realize - of their whole movement, which is pursuing its ill-chosen aims with absolutely no regard for the damage and distress that it might threaten to everyone including, the end, farmers themselves.

Everybody has the right to protest and to be heard. But nobody has the right to press his causee by harassing and endangering a random selection of his fellow citizens unlucky enough to be caught behind a road-block. The demonstration on Route 66 were, in fact, a rather ugly sequence in which tractors hit a couple of police cars and a policeman who was on foot. Holding motorists hostage, by violence, is not permissible. Speaking of symbols, that incident ended with a tractor standing sadly by the side of the road, its back tires blown out by a police shotgun. That offers a pretty accurate picture of the conclusion toward which the demonstrators' present course is taking them.

But if doesn't have to end that way. If these farmers choose to regard everyone else on the road as their enemies, from whom nothing can be obtained except by force, they are bound to be the losers. But we have been arguing on this page for some time - apparently without a great deal of success, so far - that there is a broad middle ground where the interests of farmers and consumers meet. Both have a strong interest in price stability. That means ending the wild market swings that have greatly increased the risk of farming over the past six years. The answer is a program of building national grain reserves Farmers need to know, when they plant their crops, approximately what the selling price will be. Farming ought not be a roulette game in which extremely hard-working men and women are required to put their whole livelihood at stake on the weather and on the market every year. Farmers, and everyone else, are entitled to the kind of price stability and assurance that reserves can provide.

Instead, these demonstrators are pressing for a big increase in grain prices. If they got it, the first victims would be other farmers - the cattlemen and poultrymen who buy grain for feed. But eventually even the grain farmers themselves would suffer. The present demonstrations, in fact, mark the mornifer. The present demonstrations, in fact, mark the morning-after that followed the great euphoric binge in farm prices in 1972 and 1973. Because grain suddenly brought higher prices on the market, farm land was worth much more. Now the farmers have been stuck in a falling market with extremely high land costs, high taxes based on them - and a steady inflation in manufactured goods, in part due to rising food prices in years past.THe process is circular. Simply raising prices for the farmers won't help them for long.

In fact, these demonstrators don't seem to know much about national farm policy, or markets, or political strategy. Among farmers themselves, these people are outsiders, without much leadership. They aren't being steered, or even supported, by the country's large farm organizations. The leaders to whom they would naturally look - in successive administrations, in Congress, in the farm organizations - have continued to tolerate, year after year, radical and perilous instability in the agricultural markets. That is what has brought these demonstrators - frightened, confused and increasingly vehement - onto the highways and into the capital.