Grad school is, as I mention below, all about delayed gratification. The slow-motion process of research itself, of interpreting the findings into something another human being might possibly understand or care about, of applying for grad school itself, then grants, then (dare I say it) jobs. So it was kind of exciting to see that the fact that I spend day in, day out researching 19th century assimilation; trying to frame that research in a way that might make sense to someone who isn't me and hasn't read that particular microfiche; and attempting to figure out how whatever it is I've found will translate into a dissertation or (a girl can dream) a career; has led to my having something akin to authoritah on the topic.
But for France, not the US. So while I can't (without reading up on it) offer my own take, in response to Douthat or anyone else, on the particularities of Teddy Roosevelt's thoughts on eugenics, I can weigh in on the more general question of what it means to be "pro-assimilation." Here goes...
Oh, and a disclaimer: I go on and on, but the main part of my answer to MSI, Fuzzy Face, and Douthat is in bold below.
First, let's get this out of the way: individuals aren't (often) purely progressive or purely traditionalist, purely Constitutionalist or culturalist, however we're looking at this question. And what might have counted one way in one era probably looks different or the next. And individuals tend to fall somewhere on a spectrum. Pardon my French, but Zola, hero of the Dreyfus Affair, wrote a not-so-flattering novel about Jewish bankers, while anti-Dreyfusard hero of right-wing nationalism Barrès had a moment of post-WWI epiphany that Jews can be French after all.
Anyway, there are not Two Americas, but the necessities of conceptualization are what they are. I don't think it makes sense to dismiss my argument - or Douthat's, for that matter - simply because we didn't, in the course of a short article or post account for this diversity. A generous reading of either of us assumes that anyone with half a brain knows that people come in more than two 'types.' I'm not a fan of the trend in academic writing to equivocate as though nuance means never arriving at an argument. So, these are just arguments, without which there'd be no discussion.
Also obvious, but missing so far from the discussion: assimilation goes both ways. Much of America's specific culture relates to where our population came from. Pizza, rap, words like "schlep," these owe nothing to the Noble Anglo-Saxon Tradition. This is all partly an argument over whether we're calling aspects of our culture that we can trace to WASPs superior to ones with different roots.
MSI, I will now get to the pressing question of Mormons. I'm not sure how that much fits into the topic of assimilation, as opposed to, I don't know, rule of law? Mormons had not been doing things the way they had since time immemorial, nor were their cultural (esp. marital) particularities specific to a different ethnic or racial background, as you point out. So however harsh the government was with Mormons, the goal was getting a bunch of people 'like us' to stop rebelling and being different and return to being 'like us.' Unless there's an aspect to this episode that I'm unaware of, I'm assuming a Mormon who refused to be polygamous went on to be accepted (as in, not oppressed, not not mocked - even WASPs are mocked) in mainstream America, and that a Mormon who converted to mainline Protestantism would have simply morphed into a undifferentiated Real American. The issue with Mormons was, I'm thinking, not terribly unlike that with Protestants in France - the 'problem' was their behavior, but they were a conversion away from unhyphenatedness.
As a point of comparison, take Napoleon's insistence on assembling a formal committee of French-Jewish leaders, over a decade after French Jews has been legally French, and asking them in all seriousness whether Jews practice polygamy. In terms of the absurdity of the question, imagine asking a bunch of Jews on the Upper West Side in 1990 whether they practice polygamy. That the Jews explained that they were monogamous ultimately failed to convince Napoleon, who went on first to convene another official meeting of Jews, because one can never be too sure, and ask them the same thing, and then, upon receiving yet another satisfactory answer, decided to go ahead anyway and create a law of exception discriminating against most of France's Jews, effectively revoking their newly-won citizenship. This episode, too, was about assimilation and the incompatibility of polygamy with Western modernity. But here, "polygamy" was not the practice of having multiple wives, but a pretext given for exclusion of a population that was, in its way, very much in favor of assimilating.
This diversion into my narrow area of expertise is to point out that demands of assimilation come in two forms. (Or infinite forms - if you'd prefer to do so, think of it as a spectrum.) On one side are demands that could easily enough be met, even if there's resistance at first: requests like 'don't be polygamous' or 'speak English' or 'attend public school' or 'get rid of that impossible-to-pronounce last name' are impositions of Western ideals, etc., etc., but can be met by all, assuming social exclusion doesn't stand in their way. A postcolonial studies prof might not like it - and I might not like it either, raging lefty I apparently am - but these need to be categorized differently from unmeetable requests. By this I mean demands that aren't so much demands as they are assertions that They will always-and-forever be too different. Examples: 'don't be from a religious tradition that was polygamous in biblical times,' 'don't have dark skin,' or 'marry into the general population at a time when the general population isn't open to marrying minorities in the first place.'* Any demand that asks someone to change something they can't - either because the trait is immutable or because social exclusion is too great of an obstacle - isn't so much about offering conditions for how to become an American as it is about asserting the eternal non-belonging of certain groups of Americans. Who does and doesn't belong is constantly shifting - again, because a Mayflower-only request wouldn't yield a whole lot - but the principle itself stays constant.
Finally, to return to Douthat's argument, what I understand it to be, and why I'm still not buying it. This will, I think, address MSI and Fuzzy Face as well. If what Douthat were saying was simply that various measures - insistence that immigrants speak English, or alter their names, or reign in their polygamy - repel today's well-meaning multiculturalist PC-types, but have historically served to help minorities blend in, then I don't think he'd have said anything terribly controversial, and aside from the PC-types in question and your college postcolonial studies prof, no one would be up in arms. Yes, yes, demands of assimilation are a form of violence to those of different but equally valid cultural traditions, etc., etc., but this is a different discussion. The question of whether the West should impose its values on immigrants is a real one, but it's one that assumes everyone could become Western, questioning only whether this is a fair thing to ask of non-Westerners. Boundaries shift, but traditionally this whole discussion has been an internal one among liberals. Today, the position that one should ask ferners to change in any way has become in the US, associated with the right. In France, that's not quite as much the case. But wherever the debate is situated on the political spectrum, the fact remains that there's another whole set of people who don't want to deal with Them in the first place, don't think they have a shot at assimilating.
What Douthat did, however, was to conflate genuine pro-assimilation requests with the assimilation request used as a proxy for a quite different demand, namely that ferners stay away or wear a coned hat or whatever. The cultural-rather-than-Constitutional America, the second America, encompasses both, by his definition, which is a lumping-together I don't think makes sense. So, I'll refine - no, revise - my argument to explain that I'm not calling second-America-as-Douthat-defines-it xenophobic, only a subset thereof. And I think, if we're going to divide America in two, it makes far more sense to separate those who think immigrants can become American (whether by changing their ways or simply by having their papers in order, if that) from those who believe in an essential Americanness not open to all. But, Douthat counters, refining his own position, it's impossible to divide requests that immigrants assimilate into categories of well-meaning and xenophobic. Nativists and assimilationists are often one and the same set of people. Yes, everything is ambiguous, but, I counter, it is quite possible - necessary, even - to divide requests into those that seem possible for the ferners in question to meet, and those that are so outrageous, so unattainable, as to amount to exclusion disguised as a request for assimilation.
*This is, in a nutshell, my dissertation topic, but for France. I point this out both by way of an explanation for the length of this post - I find this stuff endlessly fascinating - and also as a disclaimer re: my weakness in terms of specifics of US history. I won't, for instance, get into MSI and Britta's debate about the reasons for anti-Chinese sentiment in pre-eugenics California.