This leads us to the irony of racist opposition to immigration. Qian and Lichter also find that during the 1990s, the rate of intermarriage between both Hispanics and whites and Asians and whites declined quite significantly. Was this a reflection of rising anti-white prejudice among Asians and Hispanics or rising anti-Asian and anti-Hispanic prejudice among whites? According to Qian and Lichter, it was neither—the main driver of this decrease in the intermarriage rate was simply that the Asian and Hispanic populations increased significantly due to immigration. As the size of an ethnic group grows larger, its members have more interactions with co-ethnics. This makes it more likely that they will have a stronger sense of in-group ethnic solidarity and that they will wind up marrying co-ethnics. To put this a bit differently, if it’s slightly easier to connect with someone of your own ethnicity (and I’d say that’s generally true), the increase in potential marriage partners from your own ethnic group will make it far less likely that you’ll look for marriage partners outside of it.

What this also means is that restrictive immigration laws, like those passed in the 1920s, can have the opposite effect—that is, it seems likely that they increase intermarriage levels. Qian and Lichter observe that the immigration restrictions of that era “effectively cut off the influx of potential marital partners with similar ethnic backgrounds, a situation that undoubtedly hastened intermarriage with other white ethnics over successive generations.” This rise in intermarriage broke down what had once been rigid boundaries separating one white ethnic group from another. “The lessons for today’s high rates of immigration seem clear,” write Qian and Lichter. “The continuing influx of immigrants, unlike in the past, has replenished the supply of potential partners for native-born Hispanic and Asian American minorities.” And as a result, the researchers suggest that the level of Hispanic and Asian intermarriage with whites might decline.