When freedom was the "peculiar institution"

What about the movement's two leaders, Thomas Clarkson (the organizer of the printing shop meeting) and William Wilberforce, the Parliament member who worked within the government to eradicate slavery? You write that they liked and respected each other, and yet, as you say, this was a fight to change a worldview. Their values were so different, it's hard to believe they managed to stay united.

It's a little hard to translate into something comparable today, because there's no single overarching moral issue like slavery, which for two generations was such a prominent thing. But Clarkson and Wilberforce agreed very deeply on that, and that's what they worked on for the roughly 45 years they knew each other. Yet they disagreed on almost everything else. Clarkson, in terms of the politics of the day, was very much a radical; he was a sympathizer of the French Revolution -- even past the point where I think he should have been, when they started lopping off people's heads in large numbers. He was strongly in favor of more rights for women, universal education, labor unions and their equivalents -- democratizing impulses of all kinds. Wilberforce was very reactionary on all these things. He thought women should stay in the home, was terribly against the French Revolution and all it stood for. Yet I think that reactionary stance made him quite an effective spokesperson for the cause in Parliament, because of course Parliament was filled with conservative landowners whose politics were just like his.

One of the more surprising connections you make, that I don't believe is widely known, is that fear of the British Navy press gangs, who would kidnap men to make them serve their country, inspired the abolitionist fervor within England.

The press gangs didn't come to an end until after the Napoleonic wars were over. I was asking a question that many historians have asked for a long time, which was: Why did this movement happen in England? There was such a huge, widespread movement there, and there was nothing in any of the other six European countries that had slave colonies in the Americas -- France, Spain, Portugal, Holland, Sweden and Denmark. There was no movement even remotely equivalent in any of them. And every other explanation doesn't completely explain it. You can say that England industrialized first, but none of these other countries developed anti-slavery movements when they industrialized. You can say literacy rates were high in England, but literacy rates were higher in some of the other countries.

And then I began to think, what makes people empathize with other people of another color in another part of the world? Because that's what this movement was really about. It was the first time ever that a number of people got outraged and stayed outraged for many years about the plight of other people in a completely different part of the world. I think that's more likely to happen if you have something in common with those people. One thing that made England different from the rest of Europe was that, in a sense, a large number of British male citizens were at risk of impressment all the time. The British Navy could only rule the waves because it had a huge number of sailors, and in wartime, a huge number of people were impressed by these armed gangs of kidnappers who roamed the streets of all the major ports, and sometimes quite far inland as well.

Throughout the 18th century there was this remarkable history of resistance to the press gangs -- a resistance at every level of society: riots in the streets when the press gangs kidnapped people, mayors and magistrates in port cities refusing to cooperate with the navy, lawsuits where press gang officials got challenged, a great deal of material in the press. And the analogy that was often used was, this is no better than slavery. The idea that there was something outrageous about being kidnapped and, in effect, enslaved was an idea that was out there and was talked about long before the anti-slavery movement developed.

Also, there were a sizable number of British citizens who were kidnapped in other parts of the world. The historian Linda Colley has written quite an impressive book about this, pointing out that because England ruled so much of the world but did so with a relatively small army, because the country was so small to begin with, British soldiers and sometimes British civilians were always at risk of being taken prisoner. There, too, there was a sense that there was something outrageous, and that's where the hymn "Rule Britannia" comes from: "Rule Britannia, rule the waves, Britons never shall be slaves." Somehow all this stuff was in the public dialogue in a big way before people began asking themselves, why are we enslaving other people? Because of the amount of strong feeling about slavery when Britons were a target of it, I think that made it easier for the movement to gain traction.

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