What separates Canada from the U.S.? To John Turner, we learn, it's a question of color, or rather half-tones. ''America is a black and white country,'' the Liberal leader told the Sunday New York Times. ''We are a greyer country.''

This fascinating statement points us squarely at the true issue dividing free trade's supporters from its opponents. To now, it has largely been presented as a contest over what Canada will become after the agreement is in force, with those opposed suggesting we will lose those social values and structures that make the Canadian system preferable, and those in favor assuring the public we will not.

The more illuminating division, however, is not over this country's future, but its present; not what it might become, but what it is. For the agreement represents a threat only so far as we have something precious to lose. The fall from grace the critics describe starts from a position somewhere at God's knee. So the eternal hymns to the compassion of Canadians, to our commitment to social justice, to our sense of tolerance and instinct for consensus: all in peril.

Here, indeed, is displayed the most essential ingredient of the Canadian national character: conceit. Full of our own peerless morality, we nonetheless have the gall, as we gaze adoringly into the international mirror, to scold ourselves for feelings of inferiority. Other nations are too proud, but only Canada is vain enough to think itself too modest.

UNEQUAL DISTRIBUTION

If Canadians are so compassionate, perhaps the apologists for the status quo could explain why the distribution of income remains as unequal today - to the percentage point - as it was 30 years ago? In which area of national endeavor is our commitment to social justice on display? In the unemployment insurance program, paid for in part by the taxes of the poor, which directs more than half of its benefits to the richest half of the population? In old age pensions, again subsidized by the working poor, of which less than 20% go to those on low income? Or family allowances, 55% of which go to the top two fifths of the population?

Perhaps they mean the practice of dumping more than half of all funds available for regional development programs, to help our impoverished outlying areas, into Ontario and Quebec. Or the allocation of about $5 billion annually for spending on cultural subsidies to such institutions as Stratford and the National Ballet, which so enrich the lives of welfare mothers and double-shifting foremen. Or the many more billions in tuition subsidies for the 20% of their age group who attend university, who are almost perfectly correlated with the richest 20% of the population.

Does anyone believe our tariffs and quotas, our marketing boards and price supports, which drive up prices on the most basic human essentials - food and clothing - are anything but the most regressive tax imaginable?

Does anyone seriously suggest that our foreign investment controls are really aimed at preventing the takeover of Canada, rather than providing the handful of acquisitors who bestride our economy with exclusive fishing rights in a well- stocked pool of capital? Does it then suprise anyone that five Canadian families now control almost 500 of our companies, that more than 90% of the Financial Post 500 have a single controlling shareholder, or that one of the founders of the Committee for an Independent Canada was the chairman of Brascan?

A more accurate picture of contemporary Canada would show a nation in the suffocating grip of a few powerful groups, the rest of the country left to tear itself apart for the favors of the state. It is not tolerance but greed that drives such poisonous disputes as the flap over the CF-18 contract; not consensus but choleric that is the animus of our national debates.

The Canada the apologists for protection want to preserve is a demeaning sort of Third World playground for elites, like Cuba under the Battistas - the five families who dominate our boardrooms; the Ottawa mandarins who spend their lives planning ours; the incestuous, logrolling Toronto media establishment, who while away their evenings attending innumerable awards shows for each other and their days writing articles in government-subsidized magazines on why magazines should receive government subsidies; and the whole roll-call of the privilegentsia, from the Architectural Digest subscribers in rent-controlled splendor in Rosedale to the middle-class providers and equally well-heeled beneficiaries of spending programs enacted and maintained in the name of the poor.

Perhaps free trade will not change this state of affairs; perhaps it will improve it. But it could hardly make things worse.