missions except by court-martial or address of either house of parliament. According to the ministerialist Lord Hervey, the object was to please Lord Cobham, one of Marlborough's old officers, who had lately been dismissed, and to gain over Lord Scarborough, who had formerly favoured a similar measure. It was regarded rather as a personal insult to the king than as an attack on ministers. The bill was rejected by one hundred to twelve. The protest entered on the journals by the opposition was signed by Marlborough, as was also that which followed the rejection of Carteret's motion for information as to the dismissal of Cobham and the Duke of Bolton. In March 1734, when the marriage of the Princess Royal with the Prince of Orange was announced, Marlborough proposed the introduction of a bill to naturalise the prince, and carried his motion without opposition.
In 1737 Marlborough was employed by Frederick, prince of Wales, to solicit Henry Fox's vote for the continuance of his parliamentary annuity, and was one of the ‘chief stimulators’ of the prince in the course he took. When the prince received the lord mayor and aldermen at Carlton House, Marlborough stood with Carteret and Chesterfield distributing ‘printed copies of the king's last message to turn the prince out of St. James's’ on the occasion of the accouchement of his wife (Hervey). He afterwards gave Hervey information regarding the heartless conduct of Frederick when his mother Queen Caroline lay dying.
In 1738, to the general surprise, he suddenly went over to the court, accepting the colonelcy of the 38th foot on 30 March, and becoming a lord of the bedchamber on 11 Aug. The step was attributed to the influence of his wife (Hist. MSS. Comm. 10th Rep. i. 518); and it brought on him the wrath of the old duchess, already alienated by his marriage with the daughter of Lord Trevor, who had been an enemy to the great duke, his grandfather. Walpole says that she turned Marlborough out of the lodge in Windsor Park, and further vented her spleen by blackening the portrait of his sister, Lady Bateman, who had been the adviser of his marriage. She also aimed a coarse jest at Lady Bateman's friend Fox, and became involved in legal proceedings with the young duke, in the course of which she said she had not given him Marlborough's sword ‘lest he should pick out the diamonds and pawn them’ (H. Walpole, Reminiscences).
On 26 Jan. 1739 Marlborough was named lord lieutenant of Oxfordshire and Buckinghamshire, and on 1 Sept. received the colonelcy of the 1st royal dragoons. On 6 May following he was further gazetted colonel of the 2nd troop of horse guards, and on 20 March 1741 received the Garter. His new political attitude brought him, on the rejection of Carteret's motion for the removal of Sir R. Walpole, to the assistance of the falling premier with a motion, 13 Feb. 1742, ‘that an attempt to inflict punishment upon any person without allowing him an opportunity of defending himself, or without proof of crime, is contrary to justice, law, and the usage of parliament, and a high infringement of the liberty of the subject.’ This was carried nem. con. (Parl. Hist. x. 1223, xi. 1063 &c.; cf. Coxe, Mem. of Sir R. Walpole, i. 669). Five days later Horace Walpole told Mann that the Prince of Wales would not speak to him.
At the battle of Dettingen (27 June 1743) Marlborough commanded a brigade and did good service; but immediately afterwards he and John Dalrymple, second earl of Stair [q. v.], resigned their commissions in disgust at the conduct of the Hanoverians. Walpole, writing to Mann on 30 Nov., attributes his action to a wish ‘to reinstate himself in the old duchess's will,’ and adds a caustic remark of the latter on the occasion.
Marlborough followed up his resignation by seconding in a strongly worded speech Sandwich's motion (31 Jan. 1744) declaring ‘that the continuing the Hanoverian troops is prejudicial to the king’ (Parl. Hist. xiii. 553, 564–6). But in the following month, when news came of the approaching Jacobite rising, he moved for an address ‘to assure the king of standing by him with lives and fortunes’ (Walpole to Mann, 16 Feb. 1744), and he was one of the first to raise a force against the rebels.
On 30 March 1745 he was gazetted major-general, and on 15 Sept. 1747 lieutenant-general. He was created D.C.L. of Oxford on 4 June 1746, and had been elected F.R.S. in January 1744. On 12 June 1749 he became lord steward of the household, and was sworn of the privy council. On 22 Jan. 1751 he moved that the ‘constitutional queries’ circulated by the Jacobites against the Duke of Cumberland should be burnt by the hangman; and in 1753 spoke as a member of the cabinet council in the debate on the charges made against the preceptors of George, prince of Wales. Next year, by means of lavish expenditure, he procured the return of whigs both for Oxford and Oxfordshire, though the county had long been considered ‘a little kingdom of Jacobitism.’ On 9 Jan. 1755 he succeeded Gower as lord privy seal, and on 21 Dec. became master-general