IT'S IMPOSSIBLE not to be impressed by the sincerity and anxiety of the farmers who have come to Washington. As they talk, you perceive that they are less concerned about current prices, or the last harvest, than about the future of a kind of life in farming. They speak movingly of the family farm, the embodiment of many cherished American values. Three decades ago -- that is, well within the lifetimes of most of the demonstrators -- one out of every six Americans lived on a farm. Today it is one out of every 27. That is striking testimony to the rise in agricultural productivity over the past generation. But it also raises a question about the survival of family farming in this country.

The demonstrators on the Mall are pushing demands that would, unfortunately, actually harm the family farm and speed its demise. That puts them in an old and established tradition of perverse farm politics. For example, they want higher price supports for their crops. Higher price supports are always immediately translated into higher values of farm land. That benefits people who already own their land. But a lot of the farmers on the Mall are renters, and their grievance is that they cannot afford to buy. All of the demonstrators speak with great earnestness of the difficulties that young people face in trying to enter farming. But the greatest obstacle by far is the steadily rising price of land.

Conversely, while there are things that a government could theoretically do to help the family farm, those remedies would be anathema to most of our friends on the Mall. Price supports benefit all farms, regardless of size or ownership. The federal government could -- theoretically -- drop price supports and substitute direct subsidies to small operators with low incomes. But that alternative is derided by most farmers as welfare. Congress could also slow down the speculation in farm land by increasing the capitalgains taxes on it. But that would be equally unpopular among farmers, on the Mall and everywhere else.

Last fall the University of Missouri at Columbia held a highly illuminating seminar on the future of family farming. Most of the papers were presented by people who have lived with the question all their lives, and are deeply sympathetic to the idea of the one-family farm. The consensus was that family farming appeared unlikely to survive in its classic form because family farms are, in fact, competitive businesses that grow by expanding. As one economist there put it, "The greatest single threat to the family farm is other family farms." The great majority of the corporations now engaged in farming are successful family businesses that have incorporated for the same reasons that lead growing family businesses in other fields to incorporate.

A serious attempt to preserve the genuine family farm -- one on which most of the labor is performed by the family itself -- requires a rather radical intervention in the process of consolidation that is now going on. Some of the European countries -- notably France and Sweden -- have established public authorities that must pass on the transfer of land, to prevent absentee ownership and conglomeration. That departure is congenial to a European style of public policy that gives a priority to social stabilization. But in this country, farmers have always vehemently defended their right to trade their land at the best price offered on a free market.

American agriculture in the future is likely to be dominated by highly capitalized family-held corporate businesses that have accumulated their wealth over several generations. Is that bad? It will mean slightly lower prices than under genuine family farming but, you could persuasively argue, less stable production. The prospects of entering the farming business, for those not born into those established families, would not be good. We have argued in the past that higher farm price supports are not good for the country in general. It is equally true that they are also bad for the family farm itself.