A commenter on my previous post wrote that "Having open borders renders the entire concept of a country meaningless." That got me curious about the relevant history. My memory was that current restrictions on immigration date only from the 1920's, that prior to that the U.S. had effectively unrestricted immigration, with the only major exception being restrictions on Chinese immigration to the west coast in the late 19th century. I knew that Ellis Island existed, but was unsure what limits, other than checking for contagious diseases, it enforced.
Google is your friend. A little checking turned up the following information:
1. Ellis Island was only established as a federal immigration point—the first such—in 1890.
2. The first federal restrictions on immigration were passed in 1875; they excluded criminals, prostitutes, and Chinese contract laborers. Congress passed the first general law restricting immigration in 1882, banning immigration from China. In 1917 the restriction was extended to immigrants from other Asian Pacific countries. Numerical immigration quotas only came in in 1921, but did not apply to immigrants from Latin America until 1965.
3. While it is hard to be certain, it does not sound as though there was any effective mechanism for enforcing restrictions in the early period. That was obviously true for immigration across land borders, and I do not think there was any enforcement mechanism covering all ports that would have prevented someone from simply walking off a ship and blending into the local population—easy to do anywhere with a significant group of the immigrant's ethnicity.
On the other hand, checking estimates
of ethnically Chinese in America, it looks as though the numbers increased slowly after 1880 and actually declined from 1900 to 1920. I do not know how reliable those estimates are, or whether they reflect factors other than legal restrictions on immigration, most obviously racial legislation restricting Chinese in America and so making it a less attractive destination.
My conclusion is that if the concept of a country is meaningless without at least nominal restrictions on immigration, the U.S. only came into existence about 1875. If the restrictions have to be real—i.e. effectively enforced—the U.S., if it exists at all, has been a country for only a few decades, making it younger than I am.
The other side of the story is public hostility to immigrants. That goes back much farther than 1875—for a very readable account of what successive waves of immigrants faced, I recommend Thomas Sowell's Ethnic America
. I am not sure to what extent the survival of effectively open immigration well into the 20th century, with the exception of restrictions on oriental immigrants, reflects a balance of political forces pro and con, and to what extent the limited ability of the federal government to enforce restrictions. It is worth remembering that, throughout the 19th century, the federal government was the smallest of the three divisions (local, state, and federal), at least judged by revenue and expenditures.
And I still do not have any clear idea of why Republicans have been more hostile to illegal immigrants than Democrats in recent years. One possibility is that it has nothing much to do with the parties, that enough voters are hostile to illegal immigrants so that the anti-amnesty pro-border fence position looked like a good way of getting votes and which party tried to exploit it more was largely a matter of historical accident.
That would fit the observation that the Democrats, while not as bad on that issue (from my point of view) as the Republicans, still engage in a somewhat watered down version of the same sort of rhetoric. The difference was most pronounced in the primaries, and it makes sense that if hispanic voters were already more likely to be Democrats than Republicans, Republican candidates would see rhetoric likely to offend hispanics as less risky, at that stage of the election, than Democratic candidates would.