One of those reasons was surely a sense of exclusivist nationalism, a "Britain for the British" sort of movement. This part of the Leave campaign was by turns implicitly or explicitly anti-immigration, and both leading up to and after the vote there have been a number of incidents of violence and intimidation across the country directed at people seen as being "foreigners". A friend of mine, an expat American who now lives in the UK, posted this to Facebook the other day:
I thought my heart was broken already, but it shattered a little more today, when another American woman I know was attacked in a Tesco parking lot. She was spat on, and screamed at, and told, "Go home, you filthy immigrant." And there's the attack on the Polish center, and the flyers delivered to schoolchildren saying Polish "vermin" should leave now, and the other reports of violence and abuse hurled at anyone who looks foreign. I thought this was my country too, but I think now maybe I was wrong.While he doubtless disapproves of spitting on people in parking lots, George Will signaled his approval for this sort of nationalism in a recent column (which you can read here), which he titled "Britain's welcome revival of nationhood". He couches his argument in terms of the political centralization of power and control in Europe, but it's really an argument about identity and community. He rails against "cultural homogenization" and lauds the desire "to live on our land, under our laws, our values and with respect to our identity".
What Will is blithely assuming here, of course, is that we have a common understanding of who is "us" and who is "them". Moreover, he is also assuming (without saying so) that the best way for humans to live is for all of "us" to get together in our community, and all of "them" to go live somewhere else.
This notion of homogenous, exclusive communities is popular with some (though not all) "conservative" thinkers. It's usually rooted in an unexamined base of primordialism - the notion that "nations" have an "essential" character that is deeply historical, often ancient. Britons are British, therefore, because ... well, because they're British. The history behind these groups is usually fantasy and myth, but people like it anyway.
The instinct for gathering communities of like-minded people with whom we are comfortable is an understandable one. Social psychology has long established that this is in the nature of the human-as-social-animal: the desire both to be connected to others and to be distanced from others, which social identity theorists identify as the primary purpose of groups. If I'm in a group, by definition there must be some other people who are NOT in my group - there is an "us" and a "them".
Because of those boundaries between us and them, we have an easy means of making all kinds of difficult decisions quickly and easily. Perhaps the most important of these is trust. Our resources (mental and physical) are limited, and I can't be wary of everything and everyone. Group identity gives me a quick way of understanding who I can trust (and therefore relax around, do business with, etc.) and who I can't trust.
The problem with this is that we rely for our survival and prosperity on ever-widening circles of cooperation. Despite Donald Trump's emotional claims otherwise, the world is not built around "winners" and "losers". The highest achievements of human civilization come when we cooperate with each other, which isn't possible in a zero-sum world. George Will may want to usher us back to the 17th century when we only dealt with each other "as nations", but there's a reason why that model has been eroding - it's not as good as an interconnected world in which nations matter less and cooperation among people matters more.
A lot of the argument around the Brexit has focused on these issues of economics, and reasonably so. The less interaction and cooperation, the more barriers to trade and exchange, the poorer everyone will be. The fact that so many in the UK have been left out of the benefits of being part of a larger community is a failure not of the system of interaction, but of the distribution of wealth. The profits of free enterprise are increasingly hoarded by fewer and fewer - small wonder that the masses would like to shut that system down, since it isn't going to benefit them anyway. That failure has very little to do with the EU and bureaucrats in Brussels, and a great deal with the exercise of power and greed within British (or American) society.
But there is an argument here which goes beyond the economic to the moral and social. Simply put, what kind of society do we want to live in? And what kind of citizen do I want to be within my community? Do I want to only interact with people like me and avoid others as much as possible? How do I think the stranger, the "other", should be treated? Is it OK if I draw the boundary of my identity narrowly and reject everyone outside of those lines?
These aren't "liberal" questions or "conservative" questions - they are fundamentally human questions. The answers have political implications, but the questions are not essentially political, they are moral and social. In my view, I cannot square narrow nationalism with any understanding of the Christian faith, and any attempt to do so would simply be selfishness on my part. The value and worth of every human is the same in the eyes of God. How we negotiate living nearby and interacting
with each other is a matter of details, based on (hopefully) mutual respect for a common humanity.
The only other alternative, despite Will's attempt to deny it, really is isolationism. If you want to be honestly isolationist and not interact at all with people who are different, that's fine - have at it. But if you want to live in modern society, you don't have much of a choice. And being angry at, or afraid of, other people is simply a recipe for violence. That road leads to behavior that we know we don't want. Let us stop following "leaders" who want to take us down that path for their own gain, pretending all the while that it leads somewhere peaceful.