The "national origins" feature of that 1924 law mandated that ships arriving at U.S. ports carry immigrants from countries that had provided our immigrants in the past. We liked who we were.
Immigration policy was written to reinforce the Western orientation and roots of America, 90 percent of whose population could by 1960 trace its ancestry to the Old Continent.
But since 1965, immigration policy has been run by people who detest that America and wanted a new nation that looked less like Europe and more like a continental replica of the U.N. General Assembly.
They wanted to end America's history as the largest and greatest of Western nations and make her a nation of nations, a new society and a new people, more racially, ethnically, religiously and culturally diverse than any nation on the face of the earth.
Behind this vision lies an ideology, an idee fixe, that America is not a normal nation of blood and soil, history and heroes, but a nation erected upon an idea, the idea that anyone and everyone who comes here, raises his hand and swears allegiance to the Declaration of Independence and Bill of Rights becomes, de facto, not just a legal citizen but an American.
But that is no more true than to say that someone who arrives in Paris from Africa or the Middle East and raises his hand to declare allegiance to the Rights of Man thereby becomes a Frenchman.
What is the peril into which America and the West are drifting?
Ties of race, religion, ethnicity and culture are the prevailing winds among mankind and are tearing apart countries and continents. And as we bring in people from all over the world, they are not leaving all of their old allegiances and animosities behind.
Many carry them, if at times dormant, within their hearts.
And if we bring into America - afflicted by her polarized politics, hateful rhetoric and culture wars - peoples on all sides of every conflict roiling mankind, how do we think this experiment is going to end?
The immigration bill moving through the Senate, with an amnesty for 11 to 12 million illegals already here, and millions of their relatives back home, may write an end to more than just the Republican Party.