Hillsborough, being resolved ‘not to support or oppose men but measures,’ consented to return to his old post at the board of trade provided it ‘should be altered from a board of representation to a board of report upon reference only … and that I should not be one of the cabinet (which was also offered to me)’ (Grenville Papers, iii. 294–6; see also Life of Lord Shelburne, ii. 1–3).
The functions of the board of trade, which had hitherto been in a quasi-independent position, having been thus curtailed by an order in council, dated 8 Aug. 1766, Hillsborough was appointed on the 16th. In October 1766 he refused the post of ambassador of Spain, and resigning his seat at the board of trade, was on 27 Dec. appointed joint postmaster-general with Lord le Despencer. On 20 Jan. 1768 he became secretary of state for the colonies, the appointment of a third secretary of state being considered necessary in consequence of the rapid increase of business with the American settlements. This office, however, was abolished in 1782. At the same time Hillsborough was appointed president of the board of trade, being succeeded in the post office a few months later by Lord Sandwich. Hillsborough took his opinions of American affairs very much from Francis Bernard [q. v.], the governor of Massachusetts Bay. As a reply to the circular letter sent by the Massachusetts Assembly in February 1768 to the colonies, inviting them to take measures against the obnoxious taxes, he injudiciously instructed Bernard on 21 April to insist upon the rescission of the resolution directing the letter, and in the event of their refusal to dissolve the assembly, and on 8 June ordered Gage to send a regiment to Boston. On 15 Dec. 1768, on Hillsborough's motion, eight resolutions condemning the proceedings in the house of representatives at Massachusetts Bay and at Boston were passed in the House of Lords (Parl. Hist. xvi. 476–9). In May 1769, however, the cabinet resolved to bring in a bill for the repeal of all the obnoxious taxes with the exception of tea, and on the 9th Hillsborough communicated this resolution in a harsh and ungracious circular letter to the governors. In the debate on the Duke of Richmond's resolutions on 18 May 1770 Hillsborough defended the American policy of the government with much warmth (ib. pp. 1014–1020).
In August 1772 he resigned both his offices because he would not ‘reconcile himself to a plan of settlement on the Ohio, which all the world approves’ (Walpole, Letters, Cunningham's edit. v. 401). He was succeeded by Lord Dartmouth, and on 28 Aug. 1772 was created Viscount Fairford and Earl of Hillsborough in the peerage of Great Britain. Though out of office he continued to act with the court party in giving the most determined opposition to any concessions to America. On 5 March 1778, in the debate on the second reading of the American Conciliatory Bills, he made a passionate declamation against them, and declared that it was the most disgraceful day which the country had ever experienced (Parl. Hist. xix. 842–3). On 25 Nov. 1779 he succeeded Lord Weymouth as secretary of state for the northern department. He continued to hold the same views on the American question, and in the debate on the address, on 27 Nov. 1781, he expressed a hope that ‘the independence of America would never be admitted in that house’ (ib. xxii. 661–2). On the downfall of North's administration in March 1782 he resigned office with the rest of his colleagues, and on 20 Aug. 1789 was created Marquis of Downshire in the peerage of Ireland. His last reported speech in the English House of Lords was delivered during the debate on the address on 24 Jan. 1786, when he recommended a union with Ireland ‘as the best method of connecting and consolidating the interests of both kingdoms’ (ib. xxv. 996). This had always been a favourite project with Downshire, and had been suggested by him some thirty years previously. He died on 7 Oct. 1793, aged 75.
Downshire was a well-bred, handsome man, with agreeable manners, more fitted to play the part of a courtier than that of a statesman. Though capable of making a tolerable set speech he was an imprudent and ineffective debater. His want of tact and judgment made him peculiarly unfitted for holding a delicate position in so critical a period. Even George III declared that he did ‘not know a man of less judgement than Lord Hillsborough,’ and that he would never approve of him for the office of lord-lieutenant of Ireland (letter of George III to John Robinson, dated 15 Oct. 1776, Hist. MSS. Comm. 10th Rep. pt. vi. p. 15). He was an intimate friend of George Grenville, but their correspondence does not possess any public interest (Grenville Papers, iii. lii). He was severely attacked by Junius in his first letter for exasperating the differences between this country and America. He took an active part in Irish politics, and is said to have set an excellent example to other Irish landlords by his improvements on the Downshire estates. He was elected a fellow of the Royal Society on 8 March 1764, was created D.C.L. of Oxford University on 21 May 1771, and was appointed an elder brother of Trinity House in 1781.
