As I noted in last week's review of Tamar Jacoby's essay collection Reinventing The Melting Pot, neoconservatives proclaim faith in assimilation as an excuse for not thinking hard about the quantity and quality of immigrants.

That assumption has allowed many neocons to endorse enthusiastically the Bush-Rove Illegal Alien Amnesty and Unlimited Guest Worker plan, which has otherwise proven to be about as popular as a case of salmonella.

But look at Europe. Its experience proves that the different immigrant approaches of the host countries matters less than what the immigrants bring with them. In particular, one European country has already tried out just about the entire neocon bag of assimilative tricks—with deeply mixed results.

You can still make out these four traditional Western European approaches to treating immigrants, although the European Union is blurring the distinctions between national policies. (That's another story.)

Approach #1: Multiculturalism. The Northwestern Europeans, such as the Scandinavians, Dutch, and British, have tried multiculturalism. Needless to say, this hasn't worked. Ambrose Evans-Pritchard reported in the Daily Telegraph last week:

"Holland's 30-year experiment in trying to create a tolerant, multicultural society has failed and led to ethnic ghettos and sink schools, according to an official parliamentary report. Between 70 and 80 per cent of Dutch-born members of immigrant families import their spouse from their 'home' country, mostly Turkey or Morocco, perpetuating a fast-growing Muslim subculture in large cities."[Dutch race policy 'a 30-year failure,' January 20, 2004]

Similarly, Bruce Bawer noted in the International Herald Tribune that

"from 1996 to 2001, 82 percent of the men marrying the Norwegian granddaughters of Moroccan immigrants were themselves Moroccans; another 14 percent were of Moroccan descent…"

Bawer explained:

"These marriages - invariably arranged, and often forced - have two chief motivations. One is to provide the foreign spouse with Norwegian residency rights under the 'family reunification' provision of immigration law. The other is to resist integration by injecting into the European branch of the family a fresh dose of 'traditional values'—among them hostility to pluralism, tolerance, democracy, and sexual equality… The trend in short is toward increased segregation…" [A trap for Muslim women in Europe, June 27, 2003]

Likewise, the third generation of Britain's Pakistani Muslims, the tall and surly grandsons of the short and obsequious peasants brought in to work in the mills of Northern England, was responsible for the major race riots of 2001.

Would more social integration help? Maybe not. Britain's English-speaking Caribbean immigrants are much more woven into the mainstream working class culture, with a high interracial cohabitation and marriage rate. But that doesn't keep them from committing a disproportionate share of the violent street crime.

Finally, Britain's Hindus and Sikh immigrants, typically the offspring of the subcontinent's educated middle class, are rather standoffish but are law-abiding and productive.

The simplest explanation for these patterns: the quality of immigrants matters. In Britain, the Indians do better than the Pakistanis, just as the Africans do better than the Jamaicans, because they were more carefully selected.

Approach # 2: Quarantine. Germans aren't that much more enthused about assimilating the descendents of the gastarbeiters of the 1950s than these Turks are interested in becoming assimilated. If the German public could, it would prefer to ignore the foreigners in its midst.

Approach #3: Move 'Em On!  Southern European countries such as Italy not only don't try to assimilate immigrants, they'd really like to treat them the same way the sheriff in a Steinbeck novel dealt with a freight train full of hobos. Italy encourages asylum seekers to keep moving north toward the European Union's more generous welfare states. In effect, the Italians are telling the immigrants that northern Europeans are more apt to believe strangers' hard luck stories than seen-it-all-before Mediterraneans. They're right.

Approach # 4: La Mission Civilitrice. Finally, the French have traditionally tried to do with their immigrants almost exactly what the neocons recommend here: cultural assimilation, education in civics theories, monolingualism, meritocracy, separation of church and state, and all the rest.

This may seem ironic, because nobody in Tikrit hates anybody worse than the neocons hate the French. But that's the way it usually turns out with ideologues: it's their nature to burn at the stake those heretics who deviate the most minutely.

Officially, France is what the neocons say America is: a "Proposition Nation" defined by adherence to ideological concepts rather than by descent. Indeed, the American and French "propositions" are basically identical. Which shouldn't be surprising, since the French were wildly enthusiastic about our Founding Fathers, who in turn greatly admired French thinkers like Montesquieu and Voltaire. Of course, the French Revolution didn't work out as nicely as the American Revolution, precisely because ideological propositions are of secondary importance.

Still, the French assimilation concepts are by no means bad. Over the centuries, the French successfully assimilated large numbers of immigrants from Eastern Europe, as well as some of the best educated Africans and Vietnamese.

But they've failed miserably with their huge North African Muslim population, which now makes up somewhere between 5 and 10 percent of the population. (The French are so neocon that they refuse to count by ethnicity.)

Indeed, this French neocon philosophy probably can't survive the impact of the Muslims. France's Muslims are now so poor and hostile that the most dynamic political figure, the center-right Interior Minister Nicolas Sarkozy (himself the son of aristocratic Hungarian immigrants), has called for France to junk its tradition of equality under the law and institute affirmative action for Muslims.

Similarly, Brazil, despite its endless boasting about having no race problem, recently imposed racial preferences.

The trend in France, and Brazil, follows Sailer's Law of Quotas:

"In the long run, ideology is irrelevant; instead, there will be affirmative action if at least one politically significant ethnic group is well below average in competitive ability."

It's a sad story. The term "neoconservative" once meant an outstanding social scientist with a realist perspective on race and ethnicity, such as Daniel Patrick Moynihan, James Q. Wilson, Nathan Glazer, or Father Andrew Greeley.

But, through some intellectual version of Gresham's Law, the great neoconservatives of a generation ago have been jostled aside by lesser figures whose outlook can be summed up as:

Domestic Policy: Invite the World!

Foreign Policy: Invade the World!

Tragicomically, the French have also tried the second neocon plan too, a half century ago during the Algerian War (1954-1962). (Here's my film review from The American Conservative of the re-release of the important guerilla war film The Battle of Algiers.)

According to Alistair Horne's A Savage War of Peace, after sending a half-million able-bodied Frenchmen to Algeria to fight the Arab insurgency, France realized it needed more laborers at home. So "she increased the intake of Algerian immigrant workers so that their numbers actually rose by over 30 percent in the course of the war."

Not surprisingly, importing the cousins of the rebels you were napalming and torturing did not make for a loyal Muslim population a couple of generations later.

Today, it seems crazy that the French brought the grandfathers of all those dangerous Muslim fundamentalists into their countries.

But it's important to realize that Muslims didn't appear frightening at the time. They were viewed as docile workers and Islam as a spent force, an extinct volcano. More worrisome at the time was secular Arab nationalism, but that didn't seem to pose a domestic threat.

As Paul Cella has noted, G.K. Chesterton and Hilaire Belloc had predicted the revival of Islam as a rival to the West, but they were almost alone.

Clearly, the U.S. is currently better off with compliant Latin Americans instead of resentful Muslims as the main immigrant group. Still, as The Clash pointed out, "The future is unwritten." Fifty years ago white Americans thought of African-Americans the way they think of Hispanics today: as trustworthy servants.

Things change.

Amy Chua's recent book World on Fire showed that, all across South America since the year 2000, brown and black people are finally developing ethnic self-consciousness and solidarity in the struggle against the whites who have so easily held them down for so long. This historic change of attitude has so far not had much impact on Mexico north of Chiapas. Hence it has not yet been noticed within the U.S.

Will Latino attitudes change here, as did Muslims in Europe and blacks in America?

I don't know. I don't think anybody knows. But why take the risk?

At the very least, when deciding on the quantity and quality of immigrants, prudence is a virtue.  Ask the Europeans, now it's too late for them.

[Steve Sailer [email him] is founder of the Human Biodiversity Institute and movie critic for The American Conservative. His website www.iSteve.blogspot.com features his daily blog.]