Although Arbuthnot was not a Jacobite after the fashion of his brothers, he was a Tory, for national and familial reasons. Anne was advised (and many said controlled) by Sarah Churchill, Duchess of Marlborough, who was a champion of Whig causes. In 1706, the Duchess of Marlborough fell out with Anne—a schism which the Tories were pleased to encourage. The marriage of lady-in-waiting Abigail Hill to Samuel Masham, which was the first overt sign of Anne's displeasure with Sarah Churchill, took place in Arbuthnot's apartments at St. James's Palace. The reasons for the choice of apartment and the degree of involvement of Arbuthnot in either the love match or Anne's estrangement, are not clear. As a Scotsman, Arbuthnot served the crown by writing "A sermon preach'd to the people at the Mercat Cross of Edinborough on the subject of the union. Ecclesiastes, Chapter 10, Verse 27." The work was designed to persuade Scots to accept the Act of Union. When the Act passed, Arbuthnot was made a fellow of the Royal College of Physicians of Edinburgh. He was also made a physician in ordinary to the Queen, which made him part of the royal household.