A consideration of the map will at once convince the reader, first, that Great Britain was in a position suitable to immediate victory, and secondly, that the military advisers of her Government had formed the best possible plan for its rapid accomplishment.
What was the military object of the war? The control of a seaboard: a seaboard stretching indeed through fifteen degrees of latitude and extending in its contour over far more than fifteen hundred miles, but a seaboard only. Behind it lay districts which for military purposes did not exist—untouched, trackless, resourceless. The life of the colonies, especially their life during the strain of a war, flowed through the ports.
Again, this band of territory ran from a long southern extremity, whose climate was unsuited to active work by Europeans, through a middle temperate interval to another extremity of winter fogs and rigorous winter cold. A continental climate rendered the contrast of North and South less noticeable, for the warm continental summer embraced it all, and the cold continental winter penetrated far south; but that contrast between the two halves of that seaboard was sufficient to afford a line of social and political cleavage already apparent in the eighteenth century and destined in the nineteenth to occasion a great domestic war.
Again, there lay behind this seaboard, at a distance nowhere greater than three hundred miles nor anywhere much less than two, that valley of the St. Lawrence which Great Britain firmly held; her tenure was secure in the diversity of its race, religion and language from those of the rebels and in the unity which the admirable communications of its great waterway confirmed.
Here then was a line already wholly held, the St. Lawrence, and parallel to it a line already partially held, and always at the mercy of the British fleet—the ports of the sea-coast. Up and down the belt of land between those parallel lines went the scattered bands of the rebels. Even their organised armies were loosely co-ordinated in action and expanded or diminished with the season.
The obvious strategy for the British was to cut that intervening belt in a permanent fashion by establishing a line from the St. Lawrence to the sea, so to separate for good the forces of their opponents and then to deal with them in detail and at leisure.
An accident of topography afforded to this simple problem an obvious key: just down that dividing-line, which separates the northern climate and the Puritan type of colony from the rest, a sheaf of natural ways leads from the coast to the valley of the St. Lawrence, and of these the plainest and by far the best is the continuous and direct depression which is afforded by the long, straight valley of the Hudson and continued in one easy line along the depression marked by Lakes George and Champlain. There is not upon all that march one transverse crest of land to be defended nor one position capable of natural defence, and in its whole extent water-carriage is available to an army save upon the very narrow water-shed where (according to the amount and weight of supplies) two—or at most three—days must be devoted to a land portage. But even here, between the foot of Lake George and the Upper Hudson, existed then what is rare even to-day in the New World, a road passable to guns.
Under such conditions, even had the rebellion been universal and homogeneous, the strategy imposed was evident. The sea was England’s; the English forces had but to land in force, to occupy one or more of the ports at the outlet of these ways leading to the valley of the St. Lawrence, and simultaneously to march down from that valley to the sea. They would thus cut the rebellion in half; the cut so made could easily be permanently held, and the English henceforth could operate at their choice and in increasing numbers from any point of the coast against either section of a divided enemy.
I say this was the obvious plan even had the rebellion been homogeneous or universal; but it was neither—and nowhere was it weaker or more divided against itself than on this very line of cleavage. It was precisely in the valley of the Hudson and at its mouth that the British could count upon the greatest hesitation on the part of their opponents and upon most support, sometimes ardent support, on the part of their friends. New York was thoroughly in the Royal power, and the plan of marching from the St. Lawrence down to that harbour seemed certain to conclude the campaign. Leaving such garrison as New York required, Howe sailed with 20,000 men in this opening of the summer of 1777 to attack some one of the harbours; after a cruise of some hesitation he sailed up the Delaware and landed to march on the rebel source of supply, Philadelphia. At the same moment Burgoyne set out upon his march from the St. Lawrence valley to the sea.
Each was easily successful. Washington, covering Philadelphia from a position along the Brandywine, was completely defeated. Philadelphia was in British hands before the close of September; an attempt at relief was crushed in the suburbs within a week. As for Burgoyne, his force, though it amounted to less than a division, was equally at ease. He swept easily down Lake Champlain: the American irregulars abandoned the isthmus and their positions near Ticonderoga, which were militarily identical with that pass. He pursued the enemy to the extremity of the water, and on southward up the valley, towards the water-shed, defeating every rally and confident of immediate success.