<P> The demographic impact of the slave trade on West Africa was probably substantially greater than the number actually enslaved because a significant number of Africans perished during wars and bandit attacks or while in captivity awaiting transshipment . All nations with an interest in West Africa participated in the slave trade . Relations between the Europeans and the local populations were often strained, and distrust led to frequent clashes . Disease caused high losses among the Europeans engaged in the slave trade, but the profits realized from the trade continued to attract them . </P> <P> The growth of anti-slavery sentiment among Europeans made slow progress against vested African and European interests that were reaping profits from the traffic . Although individual clergymen condemned the slave trade as early as the 17th century, major Christian denominations did little to further early efforts at abolition . The Quakers, however, publicly declared themselves against slavery as early as 1727 . Later in the century, the Danes stopped trading in slaves; Sweden and the Netherlands soon followed . </P> <P> In 1807, Britain used its naval power and its diplomatic muscle to outlaw trade in slaves by its citizens and to begin a campaign to stop the international trade in slaves . The importation of slaves into the United States was outlawed in 1808 . These efforts, however, were not successful until the 1860s because of the continued demand for plantation labour in the New World . </P> <P> Because it took decades to end the trade in slaves, some historians doubt that the humanitarian impulse inspired the abolitionist movement . According to historian Eric Williams, for example, Europe abolished the trans - Atlantic slave trade only because its profitability was undermined by the Industrial Revolution . Williams argued that mass unemployment caused by the new industrial machinery, the need for new raw materials, and European competition for markets for finished goods are the real factors that brought an end to the trade in human cargo and the beginning of competition for colonial territories in Africa . Other scholars, however, disagree with Williams, arguing that humanitarian concerns as well as social and economic factors were instrumental in ending the African slave trade . </P>

What system of government did pre colonial ghana have