In the fall of 1777 forces of the "British Army successfully captured "Philadelphia, the seat of the "Second Continental Congress, which was forced to relocate to "York, Pennsylvania. The series of military setbacks (principally the losses at "Brandywine in September and "Germantown in October) caused many in the "Continental Army and Congress to question "George Washington's leadership of the war effort. In contrast, the northern army of General "Horatio Gates had won a signal victory over "John Burgoyne's forces, compelling Burgoyne to surrender his entire army after the "Battles of Saratoga. In addition to claiming credit for the victory at Saratoga (which some historians feel was due more to the actions of "Benedict Arnold), Gates was politically well connected to Congress.
"Conspiracy" is perhaps too strong a term to use in describing varied actions taken by disaffected officers and Congressional delegates unhappy with the course of the war. Most of those involved shared the view only that Washington was a less than perfect commander in chief, and very few of their activities were coordinated. General Gates was used as a "stalking horse to replace Washington, and had himself also engaged in some lobbying for the command, but he was not responsible for the strong response within the Congress. Opposition to Washington's command in Pennsylvania was anchored by "Thomas Mifflin, a former Congressional delegate, and also the former quartermaster of the "Continental Army who had previously worked closely with Washington. His view of Washington as a rank amateur was supported by "Richard Henry Lee, "Benjamin Rush, and probably others. A number of French officers who had been commissioned into the Continental Army were also critical of Washington. These notably included "Johann de Kalb, "Louis Lebègue Duportail, and "Thomas Conway.
Thomas Conway was an Irishman who was educated in France and had served in its military. He joined the Continental Army as a brigadier general, and served with some distinction under Washington during the Philadelphia campaign, although he and Washington did not get along, and his condescending attitude annoyed other American officers as well. General Conway had been appointed as Inspector General of the Army. In October 1777 Conway began lobbying Congress for a promotion to major general, including in his writings criticisms of Washington. Washington opposed Conway's promotion, as he felt there were many American-born officers more deserving of promotion who would be upset by such a move. As part of Conway's efforts, he wrote a letter to Gates in which he was reported to have said, "Heaven has been determined to save your Country; or a weak General and bad Counsellors would have ruind ["sic] it."
General "William Alexander (Lord Stirling) received a letter from Gates' adjutant, "James Wilkinson, that contained this quotation. He forwarded the letter to Washington, who received it on November 8, 1777. This led Washington to consider the possibility that his subordinates were scheming behind his back to replace him. He was already aware that Gates in particular was politically well connected and popular due to his success at Saratoga.
Washington wrote Conway a brief letter: "Sir, a letter which I received last Night contained the following paragraph. In a letter from Genl Conway to Genl Gates he says", and then quotes the above passage. Conway immediately acknowledged having written to Gates, but denied having written the quoted passage. Conway also again criticized Washington in this letter, writing that "although your advice in council is commonly sound and proper, you have often been influenc'd by men who Were not equal to you in point of experience, Knowledge, or judgement." Washington never saw the actual letter Conway sent to Gates. "Henry Laurens did however, and sent Washington an excerpt: "What pity there is but one General Gates! but the more I see of this Army the less I think it fit for general Action under its actual Chiefs [...] I speak [to] you sincerely & wish I could serve under you."
General Mifflin, a man Washington also distrusted, and to whom Conway had also expressed concerns over the army's leadership, informed Gates of what had transpired. Gates wrote a letter to Washington complaining that "[t]hese letters have been stealingly copied" by persons unknown to him, and that he was sending the letter to Laurens, not Washington. This attitude did nothing to placate Washington, and his relationship with Gates deteriorated.
From Conway's letter Washington assumed that he and Mifflin were close. In mid-November, Congress decided to appoint Mifflin and Gates to the "Board of War. Conway's letter of resignation was referred to the board, which rejected it. Conway was given a promotion to major general, and assigned to a new post, the army inspector general. There is no evidence that any of the participants ever formally attempted to oust Washington.