In the winter of 1776-77 reports came that a general and an army were to be sent to Canada to invade the colonies from the north by way of Lake Champlain.  The news does not seem to have made a very deep impression generally, nor to have been regarded as anything beyond the ordinary course of military events.  But there was one man, fortunately, who in an instant perceived the full significance of this movement.  Washington saw that the English had at last found an idea, or, at least, a general possessed of one.  So long as the British confined themselves to fighting one or two battles, and then, taking possession of a single town, were content to sit down and pass their winter in good quarters, leaving the colonists in undisturbed control of all the rest of the country, there was nothing to be feared.  The result of such campaigning as this could not be doubtful for a moment to any clear-sighted man.  But when a plan was on foot, which, if successful, meant the control of the lakes and the Hudson, and of a line of communication from the north to the great colonial seaport, the case was very different.  Such a campaign as this would cause the complete severance of New England, the chief source for men and supplies, from the rest of the colonies.  It promised the mastery, not of a town, but of half a dozen States, and this to the American cause probably would be ruin.

So strongly and clearly did Washington feel all this that his counter-plan was at once ready, and before people had fairly grasped the idea that there was to be a northern invasion, he was sending, early in March, urgent letters to New England to rouse up the militia and have them in readiness to march at a moment’s notice.  To Schuyler, in command of the northern department, he began now to write constantly, and to unfold the methods which must be pursued in order to compass the defeat of the invaders.  His object was to delay the army of Burgoyne by every possible device, while steadily avoiding a pitched battle.  Then the militia and hardy farmers of New England and New York were to be rallied, and were to fall upon the flank and rear of the British, harass them constantly, cut off their outlying parties, and finally hem them in and destroy them.  If the army and people of the North could only be left undisturbed, it is evident from his letters that Washington felt no doubt as to the result in that quarter.

But the North included only half the conditions essential to success.  The grave danger feared by Washington was that Howe would understand the situation, and seeing his opportunity, would throw everything else aside, and marching northward with twenty thousand men, would make himself master of the Hudson, effect a junction with Burgoyne at Albany, and so cut the colonies in twain.  From all he could learn, and from his knowledge of his opponents’ character, Washington felt satisfied that Howe intended to capture Philadelphia, advancing, probably, through the Jerseys.