Ever get the feeling that American political culture has fallen so far down the rabbit hole that no one on either side of a polarizing public debate has staked out a civically responsible position?

That's how I feel about the immigration debate that's been convulsing the nation's capital and the states along our southern border this summer, as the regular flow of undocumented immigrants from Mexico has been augmented by thousands of children fleeing poverty and gang violence in Honduras, Guatemala, and El Salvador.

Faced with this problem, the country seems to have split into mutually exclusive factions, neither of which appears to grasp the distinctive character of citizenship in a liberal society.

On one side, a ragtag coalition of groups that rarely see eye to eye has staked out a fundamentally anti-political position. The coalition includes libertarians who treat nations as atavistic constructs that should be dissolved and replaced by a global free market of labor and capital; advocates for immigrant groups who think human rights require the United States to allow anyone who shows up on its border to remain in the country and be granted citizenship; and religious activists, usually Roman Catholics, who believe that Christian charity for the poor and the helpless demands that immigrants (especially when they are children) be admitted to the country and cared for by social services.

On the other side, you have the increasingly tribalistic base of the Republican Party, which is passionately opposed to non-Caucasians becoming American citizens. Does that sound too harsh? Believe me, I wish so many on the right hadn't embraced a form of identity politics rooted in racial and ethnic grievance — and that anti-immigration activists hadn't proposed sending packages of dirty underwear to the children languishing in detention centers on the Mexican border. But they have — and they did.

Morally, I'm much more sympathetic to the universalists who make up the first group. But as I've argued before, politics is not synonymous with morality. Whereas moral judgments necessarily apply universally, to all human beings equally, politics is just as necessarily exclusionary, partial, and limited in scope. It concerns how a particular community governs itself. It invariably makes distinctions between who is in and who is out, who is a citizen and who is not, who rules and who is ruled.

There is nothing shameful about this. All political communities do it, including liberal ones, and they always will do it — at least until the advent of a government of worldwide extent in which every human being automatically exercises citizenship and shares in ruling. Short of that fantasy, political communities will need to make decisions about who will be granted citizenship, who will be allowed to live within the bounds of the community as noncitizens, and who will be deported.

And it's a good thing, too. Human beings aren't spontaneously moral creatures consistently acting in their daily lives on rational-universal Kantian imperatives. On the contrary, our moral instincts need to be educated and honed, and that happens primarily through bonds of affection and attachment that are nourished and encouraged by familial, communal, and political (patriotic) ties. Human beings need politics, despite — but also because of — its ineradicable parochialism.

All of which means that the universalists are wrong to imply that everyone who shows up on or manages to make it over the U.S. border should be given a free pass and invited to stay. Secular morality and Christian ideals may well seem to demand it, but politics precludes it. Not everyone can be admitted to American citizenship without dissolving its distinctiveness, and those of us who are already citizens must be the ones to decide how many of those who would like to join our community will be granted admission.

When it comes to settling the question of how many, it's the conservative tribalists who go much further off the rails. Unlike forms of citizenship that are rooted in inherited ethnic or racial categories, liberal citizenship, especially in its American variant, leans in the direction of universalism. It is essentially creedal or ideological — meaning that as long as an immigrant embraces the ideals embodied in the Declaration of Independence and Constitution, it doesn't matter what culture or country he comes from.

Or at least it shouldn't matter.

In this sense, the passions motivating the furiously anti-immigrant faction within the Republican Party are, at bottom, un-American — because they are rooted in illiberal (racial and ethnic) notions of citizenship.

What we're left with, then, is a position situated somewhere between the universalists and the tribalists.

We need a tightly controlled border, but with relatively liberal quotas for legal immigration, some allowances made for humanitarian refugees, and a path to citizenship for those already here. We can and should debate precisely how liberal those quotas should be, how many refugees to let in, and how arduous to make the path to citizenship. In each case, the judgment should be made in light of the nation's common good, especially in its economic dimensions.

Business owners looking for cheaper labor will tend to prefer lower barriers for entry, while workers employed in low-wage and low-skill sectors of the economy will tend to favor higher barriers to prevent greater competition for already scarce jobs.

Both sides have a point, so narrowing the debate to this and related issues doesn't settle the rancorous clash over immigration. But it does have the virtue of focusing our attention where it belongs: on the question of how (and not whether) America should seek to fulfill the promise of liberal citizenship.