Campbell’s father was Member for Argyll 1766-71 on the interest of his kinsman the duke and went out of Parliament with a place. Like his father and grandfather, Campbell chose a military career. He served in the American war, in Scotland and Ireland, in Flanders in 1793 and in the West Indies in 1796. In 1797 he was on the staff at Newcastle when returned to Parliament.
Campbell had been looking for a seat for several years, encouraged by his kinsman John, 1st Marquess of Breadalbane. The latter’s connexions were with the opposition, while Campbell preferred to connect himself, through Henry Dundas, with the ministry; so when in March 1794 Breadalbane offered to support Campbell for the vacancy in Perthshire, without any political strings, Campbell sought Dundas’s approbation, only to learn that Dundas was previously engaged to Thomas Graham. In August 1795 Breadalbane encouraged Campbell to offer for Perth Burghs; again Campbell consulted Dundas, who evidently approved. This time Breadalbane overplayed his hand, in demanding the withdrawal of Dundas’s friend David Scott in favour of Campbell, whose departure for the West Indies made it unnecessary.
Campbell evidently expected to be awarded the seat when he came home, for he then wrote to Dundas, 16 July 1797:
It is perfectly clear that if the promise made to me before I sailed to the West Indies, had been adhered to, I must now have been in Parliament. As that is not the case it is equally clear that there must have been a failure somewhere.
He vowed vengeance, whereupon Dundas satisfied him that Perth Burghs did not swallow Breadalbane’s pretensions to name their Member and, if Scott now resigned, they would choose someone else ‘who will run away with it from us all’. He promised to find Campbell a seat at no more cost than he had agreed to pay Breadalbane for his expenses at Perth Burghs and added:
I think it material for you to be in Parliament as, joined to the service you are now employed in, it ... may be the means of procuring an old regiment a year or two sooner than you might otherwise do.
SRO GD51/1/198/10/51, 54.
Campbell was not kept waiting long. A month later Dundas arranged his return for Anstruther Easter Burghs through Sir Philip Anstruther.
Left without a seat in 1806, Campbell was favoured with one by Melville in 1807, regarding it as a ‘fresh mark’ of his ‘friendship’. Melville was also quite prepared to see a political opponent, Lord Rosslyn, ousted from the general staff of the army in Campbell’s favour. His pretensions in Perthshire had again been mooted, but as he was then serving in Ireland, Melville thought his prospects best at Stirling Burghs. He arrived on 8 May and succeeded after a contest.
Returned after a less severe contest in 1812, he appeared on the Treasury list of supporters. On 2 Mar. 1813 he voted against Catholic relief (as also on 9 May 1817). He voted with government in the division of 31 May 1815 and took a month’s sick leave on 28 Feb. 1816. He further voted with ministers in the divisions of 7, 17, 25 Feb. and 23 June 1817 (the latter in favour of the suspension of habeas corpus), and apparently voted against Brougham’s motion to promote the education of the poor, 3 June 1818. He seems never to have uttered in debate and did not seek re-election in 1818. He died 24 Feb. 1832.
