But what are the connections? The Trump vote is anchored by a visible cohort of working-class whites who are principally driven by racial animus. Upon their complaints are draped (by themselves and, compliantly, the media) the more decorous claims of economic hardship, but this is an evident dodge. Hillary far outperforms Trump among those earning less than $50,000 (53% - 36%). She outperforms him in nearly every region of the country: North East (+22%), Midwest (+11%), and West (+12%). She trails only in the South (-12%), where those white voters have a certain distinctive cultural and historical context. In that that specific historical and cultural context--slavery, civil war, Jim Crow, and the post-civil-rights era GOP realignment--we see the grievances of a large chunk of the Trump bloc.
How to connect that to an apple grower in Herefordshire? It is part of the American experience to see the grievances of American whites through the lens of race--so much so that we can't see that the immigrant that angers the Herefordshire orchardist is a white guy from Poland. Poles are the stand-in in the British narrative for the invading "other." It's so hard for Americans not to see this in racial terms, because for Americans everything is racial, but this is where the phenomena of Trump and the Brexit most obviously diverge.
The British don't share the history of the Alabaman. As recently as a century ago, they controlled the most powerful empire since the Romans. They ruled it from off the shore of Europe, a separation that figures hugely in their self-conception. Those on the other side of the English Channel were the others, the ones who came from time to time in boats (and later, planes) as would-be conquerors. Their otherness, of course, was not predicated on race, but nationality, place, culture, religion (sometimes), and blood.
Old rural English people scared of immigrants voted to leave the EU and old rural American people scared of immigrants vote for Trump. They're the same. They're not. Nor are the immigrants. The flavors of xenophobia are varied, and never interchangeable.
The fixation on connecting Trump and the Brexit would be harmless enough if it were constrained to election predictions. But if Trump does win in November and we have delved no deeper into the causes of that victory than to say they were the same as those who voted to leave the EU, we will have failed to understand the actual forces at work. The UK and US have very different pasts, different histories, different wounds, and different cultures. We are motivated not by amorphous, global grievances, but the very specific ones that create the world we see around us.