Secondly, the new philosophy of "Freedom" and the "Rights of man," which
formed the corner-stone of the Revolution, made the dullest realize
that, at the very least, the slave-trade and a struggle for "liberty"
were not consistent. Thirdly, the old fear of slave insurrections, which
had long played so prominent a part in legislation, now gained new power
from the imminence of war and from the well-founded fear that the
British might incite servile uprisings. Fourthly, nearly all the
American slave markets were, in 1774-1775, overstocked with slaves, and
consequently many of the strongest partisans of the system were "bulls"
on the market, and desired to raise the value of their slaves by at
least a temporary stoppage of the trade. Fifthly, since the vested
interests of the slave-trading merchants were liable to be swept away by
the opening of hostilities, and since the price of slaves was low,[2]
there was from this quarter little active opposition to a cessation of
the trade for a season. Finally, it was long a favorite belief of the
supporters of the Revolution that, as English exploitation of colonial
resources had caused the quarrel, the best weapon to bring England to
terms was the economic expedient of stopping all commercial intercourse
with her. Since, then, the slave-trade had ever formed an important part
of her colonial traffic, it was one of the first branches of commerce
which occurred to the colonists as especially suited to their ends.[3]

Such were the complicated moral, political, and economic motives which
underlay the first national action against the slave-trade. This action
was taken by the "Association," a union of the colonies entered into to
enforce the policy of stopping commercial intercourse with England. The
movement was not a great moral protest against an iniquitous traffic;
although it had undoubtedly a strong moral backing, it was primarily a
temporary war measure.