At long last a bit of light is replacing the heat that has dominated discussions of the effects of immigration on the American economy and on the very makeup of our society.

Thanks to work by a number of economists who decided to replace rant with research, and to a study by the non-partisan National Research Council (NRC), we can now consider the successes and failures of our immigration policy, and decide just what, if anything, needs fixing.

First, some uncontested facts. In 1994 there were about 800,000 legal immigrants. This compares with 1.3 million at the peak of the wave of immigrants that sought refuge and opportunity here early in the century. And remember: The native population was smaller then. So whereas we had 13 immigrants per 1,000 resident population in 1913, we had three per 1,000 residents in 1994.

Even if we throw in the 200,000 to 300,000 illegals that the National Research Council estimates enter the United States every year, we are hardly in danger of being inundated by foreigners.

So it is probably not the number of immigrants that primarily troubles those who would have us close our doors to immigrants. Rather, it is the ethnic and racial mix of the immigrants we have attracted since the immigration laws were amended in 1965 to replace a preference system that favored Western Europeans with one based primarily on family unification.

Those who would curtail immigration worry about the effect on America's ethnic makeup of the high fertility rates of immigrants, about the social costs that newcomers impose on the existing population, and about the effect of immigration on American workers, particularly those at the low end of the wage scale.

Here the NRC again provides information that is crucial to understanding the problem. If we assume that immigration continues at its present level and make other reasonable assumptions about birth rates and the like, the portion of Asians in the population will increase from three percent at present to eight percent by 2050, and the portion of Hispanics from nine percent to 25 percent.

This latter figure goes a long way towards explaining why some two-thirds of non-Hispanic whites favor curtailing the immigration flow; they foresee huge social costs in educating and caring for these immigrants and associate them with high rates of crime and with many of the problems that bedevil our big cities.

Historical Perspective A bit of historical perspective is useful at this point. Even the most vigorous critics of current immigration policy worry very little about Asian newcomers. New Yorkers have Koreans to thank for the ready availability of fresh fruit, flowers, and vegetables, and the city's culture mavens flock to the Met, Carnegie Hall, and other venues to hear Yo-Yo Ma, Midori, Wu Han, Cho-Liang Lin, and other sons and daughters of Asia.

Yet in the last century we passed the Chinese Exclusion Act and, in 1924, the Japanese Exclusion Act in response to then-widely held fears of the negative impact of "coolie labor" on the wages of American workers and opium-puffing Chinese on our standards of morality. We were wrong.

Then there are the Eastern and Southern Europeans, now regarded as part of the great American success story, and not only in New York, where descendants of Italian immigrants hold City Hall and one of the state's senate seats, and a descendent of Eastern European immigrants serves as our governor. It was not always thus. In the 1920s, Congress enacted legislation to favor Northern Europeans, a policy that now looks foolish, in light of the subsequent success here of Southern and Eastern Europeans. So history suggests that our worries about the burdens that might be created by earlier immigrants have proved unfounded.

That does not mean, of course, that we might not be right to worry this time. After all, the new immigrants come from less well developed countries, are not as well educated as the resident population, and often have fewer marketable skills than did their predecessors. As the NRC points out, "Whether the same generational progress will characterize present-day immigrants and their children remains to be seen."

On the plus side, there appears to be no relationship between immigrant concentrations and local crime rates; new immigrants are more likely to be living in family households than the average native; and intermarriage seems likely to blur ethnic and social distinctions, hastening the assimilation of current immigrants from Asia and Latin America.

On the minus side is the fact that immigrants may put downward pressure on the wages of native-born unskilled workers, and upward pressure on the taxes of those living in states favored by immigrant groups.

The questions we face as a nation are how to balance these and other pluses and minuses, and how to increase the benefits and reduce the costs of immigration. We could, of course, surrender to such articulate and persistent pleaders for a more restrictive immigration policy as National Review's John O'Sullivan, Forbes' Peter Brimelow (both born in England), and columnist-candidate Pat Buchanan, the populist ally of the anti-immigration trade unions, and declare a moratorium on immigration.

But that would deny us the injections of yeastiness and spice that have historically forced natives who are comfortable with the status quo to compete with newcomers, or cede pride of place to them. Where would America be now if it had relied only on its old-line WASP population for the drive and skills needed to compete in a global economy? Probably less well off.

So, too, with new immigrants. The NRC finds that we have benefited a bit from continuing to welcome immigrants, even after factoring in the costs they impose on our schools and other institutions.

In the end, our problem is not immigration, but flaws in our own policies: We have failed to impose stringent English-learning requirements and other pressures on the newer immigrants; we refused until recently to attempt to restrict their immediate access to welfare benefits; and we won't increase above a mere 10,000 a year the number of visas for foreigners with the financial means of establishing businesses here.

Fix those problems, and we can remain, if not a melting pot, at least an agreeable stew.

Irwin M. Stelzer is director of regulatory policy studies at AEI.