As it was not an administrative, so neither was it a military centre. It commanded no great system of interior highways, and it was comparatively difficult to protect by the fleet. It might be argued, on the other hand, that because Philadelphia was the largest town in the United States, and possessed of a certain preëminence as the seat of Congress, the acquisition of it by the invaders would give them a certain moral advantage. It would help the Tory party, and discourage the patriots. Such a gain, however, would be trifling compared with the loss which might come from Howe's failure to coöperate with Burgoyne; and so the event most signally proved. [Sidenote: Effect of Lee's advice] Just how far the Howes were persuaded by Lee's arguments must be a matter of inference. The course which they ultimately pursued, in close conformity with the suggestions of this remarkable document, was so disastrous to the British cause that the author might almost seem to have been intentionally luring them off on a false scent. One would gladly take so charitable a view of the matter, were it not both inconsistent with what we have already seen of Lee, and utterly negatived by his scandalous behaviour the following year, after his restoration to his command in the American army. We cannot doubt that Lee gave his advice in sober earnest. That considerable weight was attached to it is shown by a secret letter from Sir William Howe to Lord George Germain, dated the 2d of April or four days after the date of Lee's extraordinary document. In this letter, Howe, intimates for the first time that he has an expedition in mind which may modify the scheme for a joint campaign with the northern army along the line of the Hudson. To this suggestion Lord George replied on the 18th of May: "I trust that whatever you may meditate will be executed in time for you to coöperate with the army to proceed from Canada." It was a few days after this that Lord George, perhaps feeling a little uneasy about the matter, wrote that imperative order which lay in its pigeon-hole in London until all the damage was done. [Sidenote: Washington's masterly campaign in New Jersey, June, 1777]