In the 20th century, historians were divided over whether Dundas should be held solely responsible for prolonging the slave trade. Historians of the slave trade and the abolitionist movement, including
David Brion Davis,
Roger Anstey,
Robin Blackburn, and Stephen Tomkins commented that Dundas's actions delayed rather than facilitated abolition.
[32][33][34][35][36] According to Davis, "By making the abolition of the slave trade dependent on colonial reforms, Dundas suggested possibilities for indefinite delay."
[32] Stephen Mullen, a research associate at Glasgow University, called Dundas "a great delayer" of abolition in 2021.
[37] These claims were criticized by historian
Angela McCarthy, who rejected the notion that Dundas's actions were so singularly determinative of the course of events.
[38]
Other historians of British history argue that delay was inevitable. Angela McCarthy notes that the revolutionary wars with France, and opposition in the House of Lords and in the royal family, presented enormous obstacles.
[39] Sir
Tom Devine, whose publications include editing
Recovering Scotland's Slavery Past: The Caribbean Connection (Edinburgh University Press, 2015), has said that blaming Dundas solely for delay in the abolition of the slave trade ignores the wider political and economic factors that were the true causes of delay.
[40] In another
Scottish Affairs article, McCarthy held that leading anti-Dundas activist Professor Emeritus Sir Geoff Palmer repeatedly misrepresented published sources.
[41] Brian Young notes that in 1792, the motion for immediate cessation of the slave trade was heading for certain defeat. By inserting the word "gradual" into the motion, Young says Dundas ensured a successful vote for the ultimate abolition of the trade in slaves.
[42]