was: Would I support continuing mass immigration if “a policy of strong assimilation [were] enforced”? Assimilation is not exactly a policy, but it is a thing that can be expected to happen more often when particular policies are in place. The abolition of bilingual education, which Jonah mentions, is one of those policies. So, I would argue, is a reduction in immigration levels. The more assimilative policies and attitudes are in place and the stronger they are, the greater the number of immigrants it would be healthy for the country to take in; the relation Jonah is getting at is real. But under any mix of other policies, you would have more assimilation with less immigration.
Jonah wants answers that do not depend on the improbability of the adoption of strongly assimilative policies. Fair enough. But it is reasonable to assume that continued mass immigration will make such policies even less likely. Leave aside the question of whether the new immigrants want assimilation, and policies that promote it. The fact is that millions of native-born Americans, and not only ideological liberals, will find multiculturalism a plausible answer to increasing levels of racial, linguistic, and cultural diversity.