I've recently been reading a fair amount on the American Revolution, especially David McCullough's 1776 (which should be required reading for every American).* The more you read of the Revolutionary War, the more there is to learn, especially about the vital question of how the colonists pulled off their victory over the vastly wealthier and more powerful Great Britain. The standard narrative of the American Revolution taught in schools and retained in our popular imagination today overlooks a lot of lessons worth remembering about where our country came from.
The Population Bomb: In assessing the combatants and indeed the causes of the war, it's useful - as always - to start with demographics. There was no colonial-wide census, but this 1975 historical study by the US Census Bureau, drawing on the censuses of individual colonies and other sources, breaks out the growth of the colonial population from 1630 to 1780, and the picture it paints is one of explosive population growth in the period from 1740 to 1780:
The black population was principally slaves and thus - while economically and historically important - less relevant to the political and military strength of the colonies. But as you can see above, the main driver of population growth was the free white population rather than the slave trade.
Authoritative sources for the British population during this period are harder to come by (the first British census was more than a decade after the first U.S. Census in 1790); most sources seem to estimate the population of England proper between 6 and 6.5 million in 1776 compared to 2.5 million for the colonies. Going off this website's rough estimated figures for the combined population of England and Wales (Scotland had in the neighborhood of another 1.5 million people by 1776), the colonies went from 5% of the British population in 1700 to 20% in 1750, 26% in 1760, 33% in 1770, and 40% in 1780:
It was perhaps inevitable that this shift in the balance of population between the colonies and the mother country would produce friction, and of course such a fast-growing population means lots of young men ready to bear arms. Men like Franklin and Washington were already, by 1755, envisioning the colonies stretching across the continent for the further glory of the then-nascent British Empire; 20 years later, both were buying Western land hand over fist and picturing that continental vision as a thing unto itself.
The distribution of population among the individual colonies was somewhat different from today. Virginia (encompassing present-day West Virginia) was by far the largest colony and, along with the Carolinas, the fastest-growing, while Massachusetts, Maryland and Connecticut were much larger - and New York much smaller - relative to the rest of the colonies than today:
This is one reason why Maryland gained a reputation as the "Old Line State": it had the manpower to supply a lot of the Continental Army's best troops. Connecticut was, in fact, seen as a crucial economic engine of the war, the most industrialized of the colonies at the time and mostly undisturbed by combat. That said, when you look solely at the white population, the southern states loom less large, and the crucial role of Pennsylvania and Massachusetts comes into focus:
The smaller colonies present a similar picture:
Note that Rhode Island, alone, lost population during the war, due to the 1778-1780 British occupation of Newport. That occupation had lasting effects. According to a 1774 census, Newport's population before the war was more than twice that of Providence (more than 9,000 to less than 4,000) and it was a booming seaport; the city's population dropped by more than half to 4,000, and it never really recovered its status as a port, losing business permanently to New York and Boston. Another lasting side effect: Rhode Island, founded by Roger Williams as a haven of religious tolerance and welcoming even to Jews and Quakers, forbade Catholics from living in the colony, but after the British abandoned Newport in 1780 and the French garrison took up residence, the grateful Rhode Islanders permitted the French troops to celebrate the first Mass in Rhode Island; today, it is the most heavily Catholic state in the union.
Britain's population would surge in the 1790s, and by about 1800 there were a million people in London alone, the first city in world history confirmed to exceed that threshold. But that remained in the future; at the time, France's population of 25 million and Spain's of some 10 million would easily exceed that of George III's domain. Moreover, like its colonies, England had a longstanding aversion to standing armies; while the Napoleonic Wars would ultimately compel the British Army (including foreign and colonial troops) to swell to a quarter of a million men by 1813, a 1925 analysis found that "[a]t the outbreak of the Revolution, the total land forces of Great Britain exclusive of militia numbered on paper 48,647 men, of which 39,294 were infantry; 6,869 cavalry; and 2,484 artillery," with 8,580 men in America. And those forces were always stretched; according to this analysis of Colonial & War Office figures, the British never had much more than 15,202 redcoats in the American theater (including the Floridas, where they fought Spain), and never exceeded 30,000 troops in total, counting "Hessians" (companies of professional soldiers hired from the Hesse-Hanau, Hesse-Kassel, Brunswick and other German principalities) and American Loyalists (a/k/a "Tories"):
The Close Call: More modern American wars like the Civil War and World War II eventually developed a momentum that made victory effectively inevitable, as America's crushing material advantages came to bear on the enemy. By contrast, the Revolutionary War was, from beginning to end, a near-run thing (to borrow Wellington's famous description of Waterloo). At every stage and in every campaign of the war, you can find both British and American victories, as well as a good many battles that were fought to a draw or were Pyrrhic victories for one side. The length of the 7-year war in North America was a burden for the increasingly war-weary British, for a variety of reasons, but a long war was also a great risk for the Americans: the longer the war ran on, the harder it was in terms of both finances and morale to keep the all-volunteer Continental Army in the field. Whole units dissolved en masse at the end of their enlistments throughout the war, and there were mutinies in the spring of 1780 and again in January 1781. As late as 1780, Benedict Arnold's treason and debacles at Charleston and Camden, South Carolina put the American cause in jeopardy of being rolled up by the British, causing America's European allies to strike a separate peace. At one point or another in the war, the then-principal cities of most of the colonies - Massachusetts (Boston), Pennsylvania (Philadelphia), New York (New York), Virginia (Richmond and Charlottesville), Rhode Island (Newport), South Carolina (Charleston), Georgia (Savannah), Delaware (Wilmington) and New Jersey (Trenton, Princeton, Perth Amboy, New Brunswick) were captured and occupied by the British. Only Connecticut, Maryland, North Carolina and New Hampshire remained unconquered, as well as the independent Vermont Republic (Maine, then governed by Massachusetts, was also under British control for much of the war; the failed Penobscot Expedition was aimed at its recapture, and ended with a disastrous naval defeat). In the spring of 1781, Thomas Jefferson - then the Governor of Virginia - escaped capture by Cornwallis' men by a matter of minutes, fleeing on horseback as the government of the largest colony was dispersed. It was only the complex series of events leading to Yorktown in the fall of 1781 - Cornwallis retreating to Virginia after being unable to put away Nathanael Greene's Continentals and the North Carolina militia, Washington escaping New Jersey before the British noticed where he was going, Admiral de Grasse bottling up Cornwallis' escape route in the Chesapeake by sea, Henry Clinton failing to come to Cornwallis' aid in time - that created the conditions for a decisive victory and finally forced the British to throw in the towel.
Moreover, a great many individual battles and campaigns throughout the war turned on fortuitous events ranging from fateful decisions to apparently providential weather. It is no wonder that many of the Founding generation (like many observers since) attributed their victory to the hand of God.
Weather and Suffering: Both the Continental Army and its British and Hessian adversaries endured conditions that no armies before or since would put up with, including a staggering menu of extreme weather ranging from blizzards to colossal thunderstorms to blazing summer heat. Ancient and medieval armies would not campaign in freezing cold and snow; modern armies (like the combatants at Leningrad and the Marines in the retreat from Chosin Resovoir) would at least face them with something closer to proper clothing and shelter. But both sides in the war suffered chronic shortages: the British from lack of food for their men and forage for their animals, the Americans from lack of clothing (especially shoes), shelter and ammunition. The British lost more sailors to scurvy in the war than soldiers to combat, and during the long siege of Boston they had recurring problems with their sentries freezing to death at night. Smallpox, malaria and other diseases were endemic and especially hard on European troops with no prior exposure (one of Washington's great strokes of good judgment was having his army inoculated against smallpox, a disease he himself had survived and which left him pock-marked and probably sterile**). The British were rarely able to make use of their cavalry due to a lack of forage, and their infantry had other equipment problems:
[T]he flints used by the British soldier during the war were notoriously poor. Colonel Lindsay of the 46th lamented that the valor of his men was so often "rendered vain by the badness of the pebble stone." He exclaimed indignantly against the authorities for failing to supply every musket with the black flint which every country gentleman in England carried in his fowling piece. In this respect the rebels were acknowledged to be far better off than the king's troops. A good American flint could be used to fire sixty rounds without resharpening, which was just ten times the amount of service that could be expected from those used by the British forces. Among the rank and file of the redcoats, the saying ran that a "Yankee flint was as good as a glass of grog."
The war was conducted during the Little Ice Age, a period of low global temperatures (it's a myth that "climate change" is a new phenomenon or must be caused by human activity), and the winters of the period (especially 1779-80) were especially brutal. American soldiers and militia forded waist-deep icy rivers to reach the Battle of Millstone, marched miles without boots in snowstorms on Christmas Night after crossing the icy Delaware to reach the Battle of Trenton, and even tried (insanely) to lay siege to the fortified Quebec City in a driving snow on New Year's Eve. These were only a few of the examples of Americans marching great distances in weather conditions that would defeat the hardiest souls. The British performed their own acts of endurance and valor; drive over the George Washington Bridge some time and look at the cliffs of the Palisades, and picture Cornwallis' men scaling them at night to attack Fort Lee. Other battles were fought in heavy wool uniforms in the broiling heat, from Bunker Hill to much of the southern campaign, or in rains that left gunpowder useless, or - on the eve of the Battle of Brooklyn - colossal lightning strikes that killed groups of American soldiers in Manhattan. In the 1776 siege of Sullivan's Island, the British were shocked to discover that their cannonballs wouldn't splinter the soft palmetto wood from which the American fort was constructed, leaving the British ships to take a pounding from American artillery.
Except for Quebec, the weather - however hostile - nearly always managed to favor the American cause, rescuing the Americans when the hand of fate was needed most. McCullough recounts the especially significant shifts in the wind and fog that allowed Washington's army to escape in the night, undetected, across the East River after the catastrophic Battle of Brooklyn, while the blizzard at the Americans' backs was key to their surprise at Trenton.
The Allies: Most educated Americans still recall that France came to the aid of the fledgling nation after the victory at Saratoga, and played a significant role in tipping the scales in the war. In World War I, Pershing's refrain of "Lafayette, we are here" was still a popular invocation of that collective memory. Besides French money and supplies and French land and naval combat at Yorktown, the French also stretched the British defenses with extensive campaigns in the Caribbean and with a threatened invasion of England. But as important as the French alliance was, the emphasis on France understates the role that other of America's allies and Britian's enemies played in the Revolution.
First and foremost, at least as history is taught here in the Northeastern U.S., the Spanish role in the Revolutionary War is scandalously underplayed. There are reasons for this: Spain was a less impressive international power in the late 18th Century than France and would become drastically less so by the end of the Napoleonic Wars in 1815, and unlike the French, the Spanish rarely fought shoulder-to-shoulder with Americans or within the Thirteen Colonies. But Spain performed three vital roles in the war. First, under Bernardo de Gálvez (namesake of Galveston, Texas, among other places), the Spanish Governor of the Louisiana Territory, the Spanish shipped significant war materiel up the Mississippi River through the American agent Oliver Pollock, supplementing the French aid that kept the American cause afloat. Second, after Spain's 1779 declaration of war against Britain, Gálvez opened a significant second front against the British-held Floridas (which then included, in the territory of West Florida, much of what is now the Gulf Coast of Georgia, Alabama and Mississippi). Gálvez was arguably the most successful commander of the war in North America, his multi-national, multi-racial force sweeping through the British defenses, preempting any British move on New Orleans and culminating the capture of Pensacola (then the capital of East Florida) in the spring of 1781. This campaign resulted in the Floridas being transferred from Britain to Spain in the resulting peace treaty; the absence of a British foothold on the southern border of the U.S. would have lasting consequences, and the Floridas would end up being sold by Spain to the United States in 1819. And third, the Spanish played a pivotal role in the Yorktown campaign, not only raising more funds in Cuba for the campaign but also providing naval cover in the Caribbean that allowed Admiral de Grasse to sail north and close off the Chesapeake just in the nick of time. (Spain also conducted a long, costly siege of Gibraltar that ended unsuccessfully and a successful assault on Minorca, both of which spread British manpower thin between 1778 and 1783).
The other main fighting allies of the American colonists were two of the Iriquois Six Nations in upstate New York, the Oneida and Tuscarora (the other four fought with the British), as well as a few other tribes on the western frontier. But other sovereigns caused the British additional problems. The Kingdom of Mysore, a French ally in Southern India, went to war with Britain (the Second Anglo-Mysore War) in 1780, inflicting thousands of casualties with innovative rocket artillery at the September 1780 Battle of Pollilur. The Dutch, who frustrated John Adams' efforts to arrange financial assistance and an alliance until after Yorktown, nonetheless ended up dragged into the Fourth Anglo-Dutch War beginning in December 1780. (Some things never change: Adams was accused of unilateral "militia diplomacy" for ignoring diplomatic protocols and negotiating with the Dutch without consulting the French, but crowed after inking the deal in 1782 that "I have long since learned that a man may give offense and yet succeed."). The Russians, then moving towards an alliance with Great Britain against the French, nonetheless pointedly refused to get involved; Catherine the Great refused a 1775 request in writing from George III that she send 20,000 Cossacks to America (necessitating the hiring of Hessians instead) and eventually joined the League of Armed Neutrality with the Dutch and others to resist British naval embargoes (the step that brought the British and Dutch to blows). Catherine II thought the British were fools for provoking the conflict and predicted from the outset that the Americans would win. All in all, the international situation by the end of 1780 left the British increasingly isolated and drove the strategic imperative to seek out a decisive battle in Virginia - an imperative that led Cornwallis directly into a trap of his own devising but which the American, French and Spanish forces sprung with great skill and coordination.
* - Besides 1776, others I've read recently include H.W. Brands' Benjamin Franklin bio, and Joseph Ellis' George Washington bio (I'd previously read McCullough's John Adams bio and Ellis' Thomas Jefferson bio). For the beginner, relative to some other subjects, Wikipedia's writeups on many Revolutionary War battles are pretty good introductions to the chronology and sweep of the war; what Wikipedia lacks in stylistic flair and, at times, accuracy, it makes up in organization and structure. But as always, remember to never rely on Wikipedia without checking a second source.
** - We do not know for sure that Washington was unable to have children, but sterility was a common side effect of smallpox for men fortunate enough to survive the disease. Andrew Jackson, who contracted smallpox at 14 during the Revolution but was the only member of his family to survive the war, also never had children of his own.
In Part II: Washington and the other American and British generals and the role of the militia.