It’s worth remembering that the British debate over the United Kingdom’s proper relationship with the EU is not new—certainly not as new as the broad-based backlash to free trade that’s helping to drive the 2016 American election. Not even close. And more than likely, it won’t end with Thursday’s vote.

In fact, the United Kingdom has been fighting this raucous, existential battle for more than forty years now. There was a referendum on staying in the EU in 1975, after all, just two years after Britain joined the European Economic Community—the precursor of the EU—in the first place.

And the Brexit vote centers on a bitter struggle for power in the Conservative Party. The very reason Britain is voting today on whether to leave the EU at all is that Prime Minister David Cameron made a decision—a severe miscalculation, most observers here now say—to cover his right flank by catering to the Euro-skeptics in his ranks with a referendum.

Moreover, the pro-Brexit campaign, which gets much of its support outside London, spans a very different sort of political spectrum than Trump’s coalition.