What if Brimelow’s call for a moratorium had been acted upon? Twenty years on, we can reconstruct two different scenarios for the period 1992 to 2012: the actual one, in which immigration rises throughout the period, and the Brimelovian ideal, in which an immigration moratorium is imposed. 
In 1992 the U.S. population was 255 million. Extrapolating from the Census Bureau’s latest population figures, we estimate population is currently 314 million, up by 59 million, or 23.1%, over the past 20 years.
Had a moratorium been in place U.S. population would be about 288 million—26 million below its current level.
That 26 million equals 8.3% of U.S. population. It is equal to the combined populations of Wyoming, Vermont, North Dakota, Alaska, South Dakota, Delaware, Montana, Rhode Island, Hawaii, Maine, New Hampshire, Idaho, Nebraska, West Virginia, New Mexico, Nevada, Utah, Kansas, and the District of Columbia. Or, to put it, another way, we imported Mexico City  and Istanbul combined.
Of course, population growth is not the whole story. The demographic effects of a 1992 moratorium are at least as important.
By 1992, immigration had already pushed the U.S. minority population  to record levels . And, over the subsequent 20 years, non-white mothers (immigrant and native-born  alike) continued to have significantly more children  than their white counterparts .
Thus over the entire twenty-years, 1992 to 2012, the white-alone, non-Hispanic population grew by 3.7%.—or by a mere 0.2% per annum. Over the same period, the minority population—defined as persons not identifying themselves as white alone and non-Hispanic—grew by 81%.
Among minority groups, non-Hispanic Asians  grew fastest, up 127%. The Hispanic population rose 119%. Non-Hispanic Blacks were up 36%.
A moratorium would have dramatically slowed the minority growth rate:
If the actual 1992-2012 trend remains in place i.e. if current immigration continues, we estimate non-Hispanic whites are destined for minority status in 2032 . (Note to Karl Rove: this is not the same as the electorate, which will remain majority white much longer ).
But had a Brimelovian moratorium been in place since 1992, our projection shows that the majority/minority year would have been pushed back to 2077—for practical purposes indefinitely, certainly well beyond the life-time of the readers of the original article in 1993 (and of virtually everyone reading this today).
Of course, the fact that American whites might eventually go into a minority at all is remarkable—a measure of the unprecedented demographic revolution imported, in less than thirty years, by the 1965 Immigration Act and what appears to have been the simultaneous tacit bipartisan  decision to cease enforcing the law  against illegal immigration .
But, remember, a projection this far out depends on certain heroic assumptions:
- The minority fertility rate has to remain high.
But it is quite possible that this may not happen—indeed, that it is already not happening. For example, the Pew Research Center,  focusing on recent declines in immigration and fertility rates, projects whites will become a minority of the population (47%) only by 2050—two decades later than our estimate (which extrapolates using the higher growth rates experienced over the 1992- 2012 period. ).
- The white fertility rates has to remain low.
Among Hispanics the total fertility rate —the number of children a women is predicted to have over her lifetime—is 2.4 . For non-Hispanic whites it is 1.8. The replacement rate is 2.0. If white fertility rates remain below that level, the white population eventually will decline.
But fertility rates are extremely unpredictable. The post World War II Baby Boom  was a complete surprise to demographers. Maybe there won’t be another white Baby Boom, but even a small increase would make a big difference over time.
- The illegal population has to remain—period.
But in fact it could be eliminated through (to coin a phrase) “self-deportation.” 
Estimates of the illegal presence in the US currently range from 12-20 million. Kris Kobach  has estimated  that up to half would leave within five years if U.S. immigration laws were actually enforced, through mechanisms like e-verify—an option usually know as “attrition through enforcement”. VDARE.com has helpfully added “strategic deportation ” to the mix. And then there’s plain old deportation. Thus some 1.9 million illegals left the US during the Eisenhower Administration’s Operation Wetback, but only 80, 000 were actually deported.  The rest just got the hint. 
(Additionally, the political impact of illegal immigration could be parried by closing the Birthright Citizenship loophole  which currently makes their children technically US citizens . We’ve estimated  that, all by itself, this could halve the GOP’s drift to demographic destruction. Switzerland  has a large , multi-generation alien community —but they don’t get to vote).
- White immigration could be increased.
An immigration moratorium is generally defined as zero net immigration, so there will continue to be perhaps a couple of hundred thousand immigrants matching the outflow. They could be white. 
Or, who knows, maybe the GOP will decide to elect (strictly speaking, re-elect) a new (historic) American people just as the Democrats have been openly boasting  about doing since 1965. For example, some 338, 000  emigrants left the UK last year, but only about 14,800 achieved permanent status here. 
It’s a paradox that all American politicians are allowed spend a great deal of time gerrymandering  Congressional districts, and even openly worrying about the electoral implications of admitting new states to the Union , but apparently they (or least Republicans) aren’t allowed to think about the electoral implications of different types of immigration. 
Yet Senator Edward Kennedy thought it was a legitimate concern—after all, during the debate on the 1965 Act, he promised 
First, our cities will not be flooded with a million immigrants annually . Under the proposed bill, the present level of immigration remains substantially the same … Secondly, the ethnic mix of this country will not be upset … Contrary to the charges in some quarters, S.500 will not inundate America with immigrants from any one country or area, or the most populated and economically deprived nations of Africa and Asia .
He couldn’t have been lying , could he?