On receiving the communications of General Sullivan, congress passed a vote approving his conduct, and that of his army.  That approbation, however, seems not to have extended beyond his conduct in the Indian country.  His demands for military stores for the expedition had been so high; in his conversations with his officers, he had so freely censured the government for its failure to comply with those demands; in general orders, he had so openly complained of inattention to the preparations necessary to secure the success of the enterprise; that considerable offence was given to several members of congress, and still more to the board of war.  From the operation of these causes, when Sullivan, at the close of the campaign, complained of ill health, and offered, on that account, to resign his commission, the endeavours of his friends to obtain a vote requesting him to continue in the service, and permitting him to retire from actual duty until his health should be restored, were overruled; and his resignation was accepted.  The resolution permitting him to resign was, however, accompanied with one thanking him for his past services.

Although these great exertions to terminate Indian hostility did not afford complete security to the western frontiers, they were attended with considerable advantages.  The savages, though not subdued, were intimidated; and their incursions became less formidable, as well as less frequent.

The summer of 1779 passed away without furnishing any circumstance in America which could be supposed to have a material influence on the issue of the war.  In Europe, however, an event took place which had been long anxiously expected, and was believed to be of decisive importance.  Spain at length determined to make one common cause with France against Great Britain.  It was supposed that the two powers would be able to obtain a complete ascendency at sea; and that their combined fleets would maintain a superiority on the American coast, as well as in Europe.

From the first determination of France to take part in the war, it appears to have been the earnest wish of the cabinet of Versailles to engage Spain likewise in the contest.

Her resentments against England, her solicitude to diminish the naval strength of that nation, and her wish to recover Jamaica, Gibraltar, and the Floridas, urged her to seize the fair occasion now offered of dismembering the British empire, and accomplishing these favourite objects.  But her dread of the effect which the independence of the United States might produce on her own colonies, mingled with some apprehensions of danger from the contest she was about to provoke, had produced an appearance of irresolution, which rendered her future course, for a time, uncertain.  In this conflict of opposite interests, the influence of the cabinet of Versailles, and the jealousy of the naval power of Britain, at length obtained the victory; and his Catholic Majesty determined to prevent the reannexation of the United States to their mother country; but to effect this object by negotiation rather than by the sword.