In a book published in 2010, I proposed that America had become a "centerless society" lacking a consensus about the highest human goods. It is this inability to agree on ultimate ideals that fuels the culture war, I argued, with some people devoting themselves to God (believing that abortion is murder, and defining marriage exclusively as a "one-flesh union" between a man and a woman) and others rejecting God (defending a woman's absolute right to terminate a pregnancy, and advocating the freedom of gays to marry).

I also proposed a solution to our cultural conflicts — or rather, a way of coming to accept them as a permanent fact of modern life. Instead of one side continually attempting to triumph decisively over the other, the American tradition of federalism might be used to allow us to live in acceptance of our centerlessness.

And now it's happening. Several states have passed significant restrictions on abortion, while many others continue to keep it freely available. A number of states have legalized gay marriage, while others resist the change. The same dynamic is now also taking shape around pot legalization, with a handful of states moving to permit marijuana purchases and some others going out of their way to reaffirm prohibition.

This is precisely what I advocated in my book.

So why am I worried?

Because I can't get Abraham Lincoln out of my head.

In theory, the American states are supposed to be laboratories of democracy, free to experiment with building different and divergent local cultures. But America has also had concrete historical experience with cultural diversity leading to serious trouble. In his legendary 1858 debate with Stephen Douglas, Lincoln famously pronounced that "a house divided against itself cannot stand" — that big cultural questions ultimately need to be decided one way or another at the level of the nation as a whole.

It took fewer than three years for Lincoln's dire prediction to be fulfilled.

What about the issues that divide us today?

The legal issues are fairly straightforward. If I had to wager a guess, I'd predict a mixed bag of results: The courts will ultimately force gay marriage to be accepted across all 50 states, some of the new abortion restrictions will be overturned but others will be upheld, and the states will be given maximum latitude to experiment with a range of options with regard to the legal status of marijuana sales and use.

The bigger problem is culture. We've all caught ourselves wondering at one time or another if the country is coming apart at the seams, with anti-abortion activists and defenders of traditional marriage squared off against abortion rights groups and gay-marriage advocates. Cable-news and talk-radio personalities, along with demagogic politicians, might exploit and exacerbate these and other fissures, but the divisions were already there — and thanks to those troublemakers, as well as a multitude of sociological factors, they appear to be getting worse.

The old talk of a red state/blue state divide got at part of what's going on culturally, but only a small and misleading part. Even the bluest state has red communities within it, and the same holds for blue areas in red states. Looked at through different lenses, our divisions can be described as regional (North vs. South; coasts vs. heartland), geographical (urban vs. rural), intrareligious (traditionalist believers vs. liberal believers), interreligious (observant vs. secular), and technological (like-minded people coming together online and forming ideologically and morally homogenous communities without regard for real-world distances).

The result looks an awful lot like the cultural fracturing of the United States.

The liberal political theory that influenced and inspired America's founders tells us that these disagreements shouldn't be a problem. First devised in response to the bloody clashes of Europe's religious civil wars, classical liberalism proposes that a modern, liberal nation can cohere around devotion to the ideals and institutions that make it possible for its citizens to live together freely and in peace, despite their differences about the highest human goods.

But is that really enough when the differences go so far beyond early modern Christian factionalism, to include disagreements about fundamental questions of life, love, sex, pleasure, family, and even the very nature of reality and meaning of existence? Is there any upward limit on how much cultural difference is compatible with national cohesion? How long are Americans stationed on different sides of our numerous cultural fissures likely to feel bound together with strangers who view the world so very differently — especially when each side increasingly treats the others with open contempt?

Can a nation of more than 310 million people bind itself together with little more than an attachment to the very institutions that permit and foster its cultural disunity?

In 1858, Lincoln predicted that the United States was destined to become "all one thing, or all the other." He found it impossible to imagine America trying to split its differences forever.

When it came to slavery, Lincoln was undeniably correct.

We have yet to determine if his ominous insight applies equally well to the innumerable issues that divide us today.