I feel a little silly debating with you about what we’re inferring that LonesomePolecat meant, but since so far he hasn’t come back to amplify or defend his ideas himself, I’ll go with this interpretation, which seems perfectly reasonable.
My response to this putative argument would be: how do we “Americanize” immigrants without emphasizing the very same “focus on ethnic and racial differences” that Putnam, as quoted by CalMeacham, says that we need to reduce?
ISTM that if we rigidly force all immigrants to conform to “mainstream American” culture—no wearing hijab (Muslim women’s clothing with headscarf) or yarmulkes, no speaking Spanish or Chinese in school or the workplace, no eating with chopsticks or tortillas or chapattis—then we may be minimizing ethnic differences among the various immigrants, but we’re over-emphasizing their differences with respect to “us”, the existing “mainstream” Americans. This is not “building the broader sense of ‘we’” that Putnam recommends for successful assimilation of diversity.
And, of course, resisting integration—keeping different ethnic groups in their own geographical enclaves—further exacerbates the focus on ethnic and cultural differences. It’s not clear to me that ethnic segregation, back in the days when large cities had their “Chinatown” and “Paddytown” and “Little Italy” and so forth, produced more harmonious inter-ethnic relations or better assimilation.
On the contrary, what we need for a “broader sense of ‘we’” is an expansion of what it means to be “mainstream America”. Americans wear hijab and yarmulke as well as baseball caps and mohawks, speak Spanish and Chinese and French as well as English, eat with chopsticks and tortillas as well as knives and forks, and so on. Yes, we need to emphasize the deeper “Americanness” that we all have in common, but we also have to share and welcome different aspects of our individual cultures.
Sure, interacting with people who are different sometimes causes stress and anxiety, but ISTM that Putnam’s saying that ultimately, that’s the only way to a stronger America. As jayjay notes, the diversity genie’s already out of the bottle. An ethnically and culturally homogeneous American society is no longer possible (if it ever was), so we’ve got to focus on ways to make a heterogeneous society work.