That doesn’t mean, however, that each side’s positions are ideologically coherent, or that the interests of the constituencies most excited about immigration within each party are enduringly compatible. It’s reasonable to expect ideological incoherence to generate instability within a political coalition over time. An ideology that embraces objectives that are incompatible under normal circumstances won’t unite the different people to whom each of those objectives is decisive indefinitely.
There’s nothing obviously incoherent about the conservative combination of statist and anti-statist attitudes. Conservatives think that redistributing the benefits and burdens generated by prevailing market structures between haves and have nots is unfair to the haves and frequently self-defeating as a way of helping the have nots. The same principles apply when the haves are documented members of the political community and the have nots are undocumented aliens. A combination of statism with respect to immigation and anti-statism with respect to intra-societal distribution makes some ideological sense.
It’s harder to see the coherence in the combination of statist and anti-statist attitudes among liberals. Granted, if you’re sufficiently committed to the principle that it’s both just and tolerably efficient to transfer resources from haves to the have nots, it might not matter much to you in principle that some of the have nots aren’t legal residents. But we live in a natural world of finite resources, and a bounded social world in which policies that are too radically redistributive are both fiscally and politically unsustainable. So immigration presents liberals with the dilemma identified by Paul Krugman:
Embracing incompatible objectives is bound to have intellectual and political consequences somewhere down the road.“Democrats are torn [about immigration] individually (a state I share). On one side, they favor helping those in need, which inclines them to look sympathetically on immigrants; plus they’re relatively open to a multicultural, multiracial society. I know that when I look at today’s Mexicans and Central Americans, they seem to me fundamentally the same as my grandparents seeking a better life in America.
“On the other side, however, open immigration can’t coexist with a strong social safety net; if you’re going to assure health care and a decent income to everyone, you can’t make that offer global.
“So Democrats have mixed feelings about immigration; in fact, it’s an agonizing issue.”