Undoubtedly the most serious army antagonist was General Charles Lee, and, but for what seem almost fatalistic chances, he would have been a dangerous rival. He was second in command very early in the war, and at this time he asserted that "no man loves, respects and reverences another more than I do General Washington. I esteem his virtues, private and public. I know him to be a man of sense, courage and firmness." But four months later he was lamenting Washington's "fatal indecision," and by inference was calling him "a blunderer." In another month he wrote, "entre nous a certain great man is most damnably deficient." At this point, fortunately, Lee was captured by the British, so that his influence for the time being was destroyed. While a prisoner he drew up a plan for the English general, showing how America could be conquered.

When he had been exchanged, and led the American advance at the battle of Monmouth, he seems to have endeavored to aid the British in another way, for after barely engaging, he ordered a retreat, which quickly developed into a rout, and would have ended in a serious defeat had not, as Laurens wrote, "fortunately for the honor of the army, and the welfare of America, Genl Washington met the troops retreating in disorder, and without any plan to make an opposition. He ordered some pieces of artillery to be brought up to defend the pass, and some troops to form and defend the pieces. The artillery was too distant to be brought up readily, so that there was but little opposition given here. A few shot though, and a little skirmishing in the wood checked the enemy's career. The Genl expressed his astonishment at this unaccountable retreat Mr. Lee indecently replied that the attack was contrary to his advice and opinion in council."

In a fit of temper Lee wrote Washington two imprudent letters, expressed "in terms [so] highly improper" that he was ordered under arrest and tried by a court-martial, which promptly found him guilty of disobedience and disrespect, as well as of making a "disorderly and unnecessary retreat." To this Lee retorted, "I aver that his Excellencies letter was from beginning to the end a most abominable lie—I aver that my conduct will stand the strictest scrutiny of every military judge—I aver that my Court Martial was a Court of Inquisition—that there was not a single member with a military idea—at least if I may pronounce from the different questions they put to the evidences."

In this connection it is of interest to note a letter from Washington's friend Mason, which said, "You express a fear that General Lee will challenge our friend. Indulge in no such apprehensions, for he too well knows the sentiments of General Washington on the subject of duelling. From his earliest manhood I have heard him express his contempt of the man who sends and the man who accepts a challenge, for he regards such acts as no proof of moral courage; and the practice he abhors as a relic of old barbarisms, repugnant alike to sound morality and Christian enlightenment."

A little later, still smarting from this court-martial, Lee wrote to a newspaper a savage attack on his late commander, apparently in the belief, as he said in a private letter, that "there is ... a visible revolution ... in the minds of men, I mean that our Great Gargantua, or Lama Babak (for I know not which Title is the properest) begins to be no longer consider'd as an infallible Divinity—and that those who have been sacrificed or near sacrific'd on his altar, begin to be esteem'd as wantonly and foolishly offer'd up." Lee very quickly found his mistake, for the editor of the paper which contained his attack was compelled by a committee of citizens to publish an acknowledgment that in printing it "I have transgressed against truth, justice and my duty as a good citizen," and, as Washington wrote to a friend, "the author of the Queries, 'Political and Military,' has had no cause to exult in the favorable reception of them by the public." With Lee's disappearance the last army rival dropped from the ranks, and from that time there was no question as to who should command the armies of America. Long after, a would-be editor of Lee's papers wrote to Washington to ask if he had any wishes in regard to the publication, and was told in the reply that,—