>I may not be the right guy to articulate it, as I don't have a deep knowledge about Us history, but in the past, other ethnics that currently are considered Am

>I may not be the right guy to articulate it, as I don't have a deep knowledge about Us history, but in the past, other ethnics that currently are considered Americans had a though time adapting, like the Irish, didn't they? Yes, indeed they did. The Irish have much much more in common, genetically, phenotypically, and culturally, with other north western European ethnic groups (the bulk of the US population at the time) than do Middle Eastern and North African ethnic groups, and it still took Irish immigrants generations to integrate into the existing population, during which time there was a great amount of friction. We came out better for it, but that is absolutely not guaranteed to happen for more distant ethnic groups. There is no reason to believe all ethnic groups are compatible enough to successfully integrate.