His hands were full of more serious work. He was plotting in the west for a rising in favour of the Stuarts. When the rebellion broke out he was arrested at Orchard-Wyndham on 21 Sept. 1715, escaped by a trick, surrendered in a few days on the advice of his father-in-law, the Duke of Somerset, and was sent to the Tower (a detailed account is given in A Full Authentick Narrative of the intended Horrid Conspiracy, 1715). Coxe (Memoirs of Walpole, i. 71), on the authority of Lord Sidney, relates that the cabinet would have overlooked Wyndham to please the Duke of Somerset had not Lord Townshend persisted in his arrest. The incident led to Somerset's withdrawal from the cabinet. Wyndham was liberated on bail in the following July, and was never brought up for trial. He was much blamed for raising the rebellion in Somerset and then running away from his responsibilities (Hervey).
Wyndham's mentor both in politics and morals was Lord Bolingbroke, who in the spring of 1715 had fled to France and committed himself to the Jacobite cause, a course to which, he said, Wyndham was the chief to urge him. Henceforth Wyndham was little more than Bolingbroke's mouthpiece in England. He laboured assiduously for the reinstatement of the high church and its principles, and in 1717 succeeded in getting parliament to appoint Dr. Snape, a high churchman and a believer in passive obedience and non-resistance, to preach at St. Margaret's on the anniversary of the Restoration. His strong Jacobite leanings were chiefly the cause of the suspicion under which the tory party rested, and which made it impotent for so many years to take advantage of whig dissensions. To Wyndham, Bolingbroke addressed some of his most famous letters from exile. The letter giving an account of the sorry experiences of Bolingbroke at the court of James in Paris was sent to him; he was the first whom Bolingbroke, disgusted with James and desiring to be pardoned by George, urged to abandon the Jacobites. To him Bolingbroke sent his well-known apology in 1717. Nine years later, when Bolingbroke was at Twickenham attempting to carry out his cherished plan of detaching a body of whigs from Walpole, Wyndham was his confidant and, under his instructions, was co-operating with Pulteney in the House of Commons, attacking the foreign policy of the Walpoles, the increase of the standing army, the pension bills, the financial administration, and drawing attention to the corruption prevalent at elections.
When, in 1728, an organised opposition to Walpole was formed, Wyndham retained the leadership of the tory wing, and gave Walpole considerable trouble. But Wyndham was Bolingbroke's mouthpiece still. When he attacked Walpole in 1730 for permitting the defences at the harbour of Dunkirk to remain undemolished, Bolingbroke's secretary investigated the matter on the spot; the series of attacks which he delivered on Walpole's finance, from the salt to the excise duties, which have been considered his finest oratorical and intellectual efforts, must be credited very largely to Bolingbroke. The heat of these debates culminated in 1734, when the Septennial Act was under discussion. Wyndham had attacked Walpole with special causticity (his speech winning from Smollett the eulogium ‘the unrivalled orator, the uncorrupted Briton, and the unshaken patriot’); the premier replied by a violent attack upon Bolingbroke. The tory policy was a failure. Bolingbroke's dream of a tory-whig opposition led by himself in the person of Wyndham proved an impossibility. When the election of 1745 renewed the whig majority, Bolingbroke again left the country, and Wyndham led his opposition with diminished heat. The correspondence with his chief was renewed, and ranged from advice given to form a coalition with the Pelhams to hunting intelligence and appeals to sell Dawley.
The chief episodes of the last few years of his parliamentary life were his support of the Prince of Wales in his quarrel with the king about his allowance, and his opposition to the convention with Spain, when he walked out of the House of Commons, followed by his party, as a protest. He knew that his tactics had been fruitless, and he discussed with Pope, shortly before his death, a project for forming a new method of opposition (Elwin and Courthope, Pope, ix. 178). Speaker Onslow's estimate of Wyndham was: ‘the most made for a great man of any that I have known of this age’ (Coxe, Walpole, ii. 560). He belonged to the gay political and literary circles which mixed together in the reigns of Anne and George, and was a leading spirit in coteries like the October Club. He was one of the founders of the Brothers' Club, of which Swift became a member in June 1711. He recommended the small poet Diaper to the members in March 1712. One of the Brothers, ‘Duke’ Disney, left him 500l. in 1731. Lord Stanhope, commenting on Pope's lines in the ‘Epilogue to the Satires’—
Wyndham, just to freedom and the throne,
The master of our passions and his own—
