General Burgoyne's defeat helps Benjamin Franklin persuade the French to join the war. The British will now be fighting on two fronts: The Americans on land, and the French, at sea.
So Washington's challenge is to keep his volunteer, untrained, and often defeated army of 14,000 together through the winter of 1777-8 so that he can take advantage of his new French allies offer. He camps at Valley Forge, Pennsylvania. A fifth of his soldiers have no shoes. In freezing temperatures, his men build 900 huts in 40 days. With little clean water, dysentery spreads, and within weeks, 2000 are sick. Meat supplies run out. With only flour and water remaining, fire-cakes are their only food. The conditions would test the most highly trained and disciplined of armies. Sixty per cent of the Washington's volunteers are made up of convicts, freed slaves and immigrants.
And then the worst the worst smallpox outbreak in US history hits his camp. His soldiers have been isolated from it for generations and have little resistance to this deadly airborne virus. Victims break out in blisters and sores. Four in 10 victims die. Washington survived it as a child and his present immunity encourages him to try a mass inoculation. Surgeons have learnt from African slaves how to harvest a small amount of pus from a smallpox victim and smear it onto the open cuts of a healthy victim. The hope is that the infection spreads at a slow enough rate that the body's white bodies attack the virus before it can become fatal. Washington's gamble pays off and the death rate falls from the thousands to the dozens as only 1in 50 of those inoculated die.
Having survived disease, famine and winter, Washington now needs to make his collection of men into an army. He tasks Baron Von Steuben with the job. His European career was ruined by rumours of homosexuality. In America, he will become one of the most important men in the military. He starts by drilling discipline into the demoralised men and moving the latrines away from the living quarters. He organises them into companies and regiments and writes a training manual, parts of which are still used by the US military today. He drills European battle tactics, such as the use of the bayonet, into an elite corps of 100 men. Each of those will train a 100 more. The men arrived at Valley Forge guerrilla fighters and survivors. They leave highly trained killers ready, eager and capable of taking on the British in open combat.
West Point, the now famous military training academy, was more or less impregnable and as its guns controlled the passage between New York and the mid Atlantic , George Washington posted an 'invalid' Regiment; wounded men who could still man guns., The British needed someone to take West Point and the turncoat, traitor, General Benedict Arnold, in return for a cool £20,000, offered to do it. In 1780 Arnold secured West Point command and would have perhaps succeeded in ending the revolution, had he not been exposed by the capture of the British spy Major Andre along with the documents revealing his intentions.
Simon Schama: The American Future