The best popular account of those weeks can be found in David Hackett Fischer's Washington's Crossing (2004) from which the quotes below are taken.
The last half of 1776 was a miserable time for Washington, his army and the cause of independence. Nothing had gone right since the publication of the Declaration on July 4. During the summer, Washington, with an army 20,000 strong, prepared to defend New York City and Long Island from a large British force which had set up its base on Staten Island.
Then, in a series of battles from late August till mid-September, Washington was outgeneraled and his army routed from Long Island and Manhattan. Further disasters ensued over the next two months capped by the British invasion of New Jersey on(Retreat from Long Island to Manhattan) November 18. For the next two weeks the British and their Hessian contingent chased the shrinking American force across the state (the chase was led by General Cornwallis who would surrender to Washington five years later at Yorktown). By early December the remnants of the American army had crossed the Delaware River into Pennsylvania. Only about 3,000 men were left with Washington. An American observer watching his army walk past in rags remarked:
"if the War is continued thro the Winter, the British troops will be scared at the sight of our Men, for as they had never fought with Naked Men."
The British believed the war was nearing an end. There were many dark days for the American revolutionaries during the war, but the days of early December 1776 were the darkest. It was during this period that Washington wrote to his brother, John Augustine Washington:
"If every nerve is not strained to recruit a new Army with all possible expedition, I think the game is pretty near up."
Nonetheless, Washington and many of his men were determined to fight on and willing to take desperate risks to keep the rebellion alive. As they observed the British forces go into winter quarters across New Jersey they began to search for an opportunity to strike back.
While they did so, other events conspired to provide them support. The Pennsylvania militia mobilized and joined Washington. In New Jersey there were spontaneous uprisings in Hunterdon County and South Jersey as armed groups assaulted isolated British outposts and foraging parties.
And Thomas Paine provided timely inspiration. Paine had already become renowned for his pamphlet Common Sense by the time he joined the American army as a volunteer in July 1776. On the retreat across New Jersey he decided to write another pamphlet and completed a draft by the time the Delaware was crossed. He called it The American Crisis and its opening words still resound today:
"These are the times that try men's souls. The summer soldier and the sunshine patriot will, in this crisis shrink from the service of his country, but he that stands it NOW deserves the love and thanks of man and woman."
The American Crisis was first published in the Pennsylvania Journal on December 19, 1776 and as a pamphlet four days later. It was immediately distributed to the camps of the army. James Cheetham, one of Paine's bitterest political rivals, wrote that it was:
"read in the camp, to every corporal's guard, and in the army, and out of it had more than the intended effect . . . Militiamen who had already tired of the war, and straggling from the army, returned. Hope succeeded to despair, cheerfulness to gloom, and firmness to irresolution."
On December 22, Colonel Joseph Reed, Washington's adjutant, sent the General a letter recommending a crossing of the Delaware and an attack on one of the British outposts. The unusual bluntness in his letter reveals the desperate and stressful nature of those days. In urging the attack, Reed wrote:
"even a Failure cannot be more fatal than to remain in our present situation. In short some enterprise must be undertaken in our present Circumstances or we must give up the cause."
"Our affairs are hasting fast to ruin if we do not retrieve them by some happy event. Delay now equals to a total defeat. Be not deceived general with small flattering appearances; we must not suffer ourselves to be lulled into security and inaction . . Pardon the Freedom I have used, the Love of my country, a Wife and four Children in the Enemys Hands, the Respect and Attachment I have to you - the Ruin and Poverty that must attend me & thousands of others will plead my Excuse for so much Freedom."
That evening after receiving the letter, Washington held a council of war and a decision was made to cross the Delaware on Christmas night and attack the Hessian garrison at Trenton early on the morning of December 26.
The attack required a hazardous night crossing of the partially frozen river, followed by a ten mile march on poorly maintained icy roads, all of which had to be done without detection in order to surprise the Hessian garrison. It was accomplished successfully and most of the Hessian force was killed or captured. The attack gave rise to the famous, and famously inaccurate, painting below (the legend is a more contemporary addition).
After its victory the army recrossed the Delaware to replenish its supplies but on December 30 they made yet another difficult crossing and set up positions around Trenton. A large force of British regulars had advanced from New Brunswick but on January 2 it was repulsed by the Americans at the Second Battle of Trenton. That evening, while Cornwallis regrouped for another attack, Washington made the daring decision to march that night around the British flank and attack Princeton.
The next day the Americans defeated the British in a battle fought in large part on the current campus of Princeton University. At a critical moment in the fight, Washington led a charge mounted on his white horse, a clear target for the British. One of his soldiers wrote his wife of that moment:
"I shall never forget what I felt at Princeton on his account, when I saw him brave all the dangers of the field and his important life hanging as it were by a single hair with a thousand deaths flying around him. Believe me, I thought not of myself."
The British retreated to New Brunswick immediately after the battle and Washington took his army to Morristown where it established winter quarters. But that was not the end of the fighting. Over the next ten weeks the Jersey Rising took place in the northeast part of the state. Local militia, irregulars and Continental army detachments fought more than thirty engagements with the British and finally drove them completely out of the state. The crisis was over.
1777 brought more challenges with the fall of Philadelphia followed by the winter at Valley Forge but that year also saw the surrender of an entire British army at Saratoga. There was never any question that we would keep fighting.