In 1732 Johnstone, whose brother had married the dowager Marchioness of Annandale, mother of the 3rd Marquess, then a minor, began
bestirring himself to set up in the [Dumfries] boroughs for himself and endeavouring to twist them out of Mr. Areskine’s hands, in which he availed himself of my Lord [Annandale]’s name and interest.
He was also supporting a candidate for the shire against Areskine. The Annandales at this time were engaged in a family lawsuit against Lord Hope, whose lawyer was Areskine. It was represented to Lady Annandale by Duncan Forbes that Johnstone’s conduct was ‘extremely offensive to the personal friends of Mr. Areskine’, some of whom were judges in the court of session, where the Annandale case was depending, and had ‘hitherto in the Marquess’s cause been of opinion with his Lordship’. He went on:
I hardly know how to express what I am next to say to your Ladyship. I ought not surely to insinuate that passions or disobligations may pervert judgment, but our judges are no more than men, and I leave it to your Ladyship to consider from what you have formerly heard or experienced, whether it is prudent, without any necessity, to give occasions for raising or playing with their passions to your prejudice.
He accordingly suggested that she should write to Johnstone, asking him to ‘lay aside his design for this time’, and to let him, Forbes, have such a letter as he could show to Areskine’s friends ‘to convince them that your Ladyship will have no hand in the opposition that Mr. Areskine ... may meet’.