Campbell was returned again for Argyllshire on the family interest in 1820 and soon afterwards married for a second time, with happier results than those of his first union. He had previously followed the partisan line of his brother, the 6th duke of Argyll, by voting consistently though very irregularly with the Whig opposition to the Liverpool ministry; but he had always been a reluctant politician and he is not known to have spoken or voted in the new Parliament. In November 1820 his wife, well advanced in pregnancy, reported her ‘delight at being relieved from the fear of his going away’: he had ‘determined to send an excuse’ and was busy planting trees at Ardencaple, which was ‘much better fun than listening to Messrs. Lushington and Co.’.
Lord John has announced his intention of retiring ... I am delighted to get out of the scrape: he is quite tired of going to London, and as his political opinions are quite opposite to the duke’s, it is needless to sacrifice one’s personal comfort, one’s opinions and interests all at the same time.
He vacated his seat early in 1822.
Campbell remained politically at odds with his brother, who held household offices in successive Liberal administrations in the 1830s. They were, as he wrote in 1831, ‘on diametrically opposite sides’ over parliamentary reform:
I considering my Lord John Russell’s bills as mixtures of tyranny and radicalism, likely to do serious and lasting injury to the British constitution, and my brother looking upon them as masterpieces of political wisdom.
Inverary Castle mss, Campbell to R. Campbell, 17 Mar. 1831.
He became a follower of Peel, in whose second ministry he held a titular office, after succeeding to the dukedom. He made an unsuccessful attempt to devise a compromise to heal the schism in the Scottish church. He was an accomplished craftsman and keen amateur scientist. His son George, 8th duke of Argyll (1823-1900), who became a major figure in the high politics of mid and late-Victorian Britain and wrote that ‘a man of sweeter nature than my father never breathed’, could not recall ‘his ever speaking on politics at all’.
He died in April 1847.
