I have been reading military history since I was a teenager, but what I am interested in has changed. I used to like books about battles, and I focused on the crazy things men did in combat. These days I am more interested in the political side of war: why are people fighting? What are they trying to achieve? How can they achieve their ends? This last question is often the most important: how can wars be won, or at least ended without defeat?
When the British attacked New York, both sides had about 30,000 men in their armies. By December, Washington had lost nearly 90 percent of his men, compared to perhaps 30 percent for the British, and the victorious redcoats chased Washington's small band of survivors across New Jersey toward Philadelphia. After their sweeping victories around New York, the more aggressive British officers wanted to press on to Philadelphia and finish the rebellion at a stroke. But the Howe brothers, who were in command, had other ideas. They let Washington escape with the battered remnants of his army and set about rebuilding royal power in New Jersey. They appointed royalist sheriffs and judges, offered a free pardon to anyone who would swear an oath of loyalty to the crown, and tried by every word and action to be and seem the legitimate authorities. At first, it worked; hundreds of men took the loyalty oath, and the royal administration began to function. To guard this new royalist Jersey, they distributed their forces across the countryside in groups of a few hundred to 2,000 men.
Then, on January 2, Washington did it again. He crossed the river again, this time with 4,500 men, his Continentals having been reinforced by Pennsylvania and New Jersey militia. The British were ready for him and responded quickly, but Washington was ready for them, too. He took a strong defensive position behind Assunpink Creek south of Trenton and waited. When British forces reached the creek late in the day, after long forced marches, and were thrown pell-mell across the creek at the Americans, they were driven back three times with heavy losses. The British prepared for a stronger and better organized attack in the morning.
The British, reeling from three defeats in quick succession, abandoned south Jersey. Inspired by Washington's victories, and by reports of British atrocities, the New Jersey militia launched a mass uprising. Thousands of men gathered and began ambushing every British patrol that left its base. At first they attacked only small parties but as their numbers and daring grew they attacked forces as large as 300 men, and soon the British feared to march with less than a full brigade. Unable to supply their men or find forage for their horses, the British withdrew from almost the whole state, retaining only a coastal strip in the north, under the guns of their warships. Their royalist administration collapsed, the patriots returned to power, and those royalists who did not flee to New York were forced to renounce their oaths and join the rebellion. Some were so outraged at the way the Royal Army had abandoned them that they signed up without pressure; stories were spread of men who tore up their signed loyalty oaths and used the paper to make cartridges for shooting at redcoats.
Thus the point was made. The British could take any city, and win any battle where they massed their men, but they could not hold the countryside; if they dispersed their forces to hold territory, the Americans would destroy them one piece at a time. It did not matter that the American soldiers were never the equal of British professionals in a stand-up fight, or that in battle Washington was an amateur bumbler compared to Cornwallis or Henry Clinton. Washington held the winning hand, politically, and after Trenton and Princeton everyone knew it. Fantasists in London continued to believe that there was some way the British could force an American surrender, but the commanders in America understood that the odds against them were very long. This realization seems to have colored many of their actions for the rest of the war; reading narratives of some campaigns it seems the British officers were more interested in surviving the war with honor than in trying to win it.
One issue that divided people at the time, and still divides historians, is how many Americans remained loyal to the crown. British policy was based on a belief that the rebels were a noisy minority, and that the majority were either loyalists or could be persuaded to loyalty by good government and a display of royal power. After the long siege of Boston convinced them that this was not true in New England, the British moved on to other parts of the country and kept on trying to rally the supposed loyalist majority. Outside New England there were quite a few loyalists in the colonies, but events in New Jersey showed that they were neither numerous nor powerful enough to matter. Most Americans either believed in independence or disliked foreign armies of occupation and saw the British as such an army. Years of war with the French and Indians had left the Americans with organized militia companies in every town and cadres of veteran men to lead them; years of effective independence had provided every jurisdiction with functioning governments as well. These facts made it impossible for the crown to conquer the whole country. Besides, most British officers were political moderates not much interested in restoring the colonies to the crown by naked force and ruling them as conquered possessions.
So in a sense the Revolution, as a war, was over before it began. All that the Americans had to do was to persevere until the British gave up and went home. Unless they chose to surrender, they could not be defeated. Washington's military role was mainly to keep up his soldiers' spirits, keep his army together as a symbol of independence, and thus make sure that the people did not surrender. From the beginning, though, he devoted just as much attention to another role, working to make the Continental Army a school for patriotism and thus weld the diverse colonies into a single nation. Defeat, he understood, was pretty close to impossible, and he never gave it much thought.