“We are,” John Adams wrote to a friend early in June 1776, “in the very midst of a Revolution, the most compleat, unexpected, and remarkable of any in the History of Nations.”

Adams was right, but it took prescience to discern it at that moment.  In the aftermath of the costly British victory at Bunker Hill the year before — a few more victories like that, one former officer observed, and British army will be annihilated  — George Washington had driven the Brits from Massachusetts, but they were on their way back with the largest armada ever sent across the Atlantic till that time.

Asked later who was primarily responsible for pushing the American colonists to embrace independence, Adams liked to cite King George III. His implacable demands made reconciliation impossible. And now Lord Germain, the king’s minister for the America colonies, meant  to crush the rebellion once and for all by a massive military blow that would destroy the fledging American army and bring the rebellious Americans to heel.

You can see the logic. The Howe brothers, General William and Admiral Richard, commanded overwhelming military force.  The Continental Army, such as it was, presented a sorry face to the world — “half starved,” as Washington later recalled, “always in Rags, without pay.” Yet the Howes, notwithstanding their mandate from Whitehall, tried desperately to avoid carnage.  They pleaded with colonial — from the beginning of July and the official declaration of independence, they were national — leaders to reconsider.  In August, after the rout of American forces from Gowanus Heights, Long Island, Howe forbore to pursue the Continental Army. That show of force, and of magnanimity, should have been sufficient. Surely, the Americans could see that resistance was futile.

Early in September, Howe convened a parlay.  Benjamin Franklin and Adams (both of whom, should the British have been victorious, would surely have been hanged) led the American contingent. A friend of Franklin’s in earlier days, Howe expressed his affection for his American cousins, adding that “if America should fall, he should feel and lament it like the loss of a brother.” Franklin, Adams recalled years later, bowed, smiled, and replied: “My Lord, we will do our utmost to save your Lordship that mortification.”

It is easy to forget now, but the summer of 1776 was a deeply inauspicious time for the American revolution. Washington’s decision to stay and attempt to hold New York was a costly, near fatal, blunder. At any point until November, when the Continental Army managed to slip away to New Jersey, the Howes, commanding absolute naval superiority as well as a vastly superior and more numerous army, could have “corked the bottle” that was Manhattan and trapped them.

An interesting question — it is a leitmotif of Joseph Ellis’s marvelous new book Revolutionary Summer: The Birth of American Independence — is whether, had the American army been destroyed early on, the rebellion would have guttered and died. The Howes never put it to the test. As Ellis shows, able military men though they were, they aspired to be diplomatists more than conquerors. They wished to return to England not as military heroes so much as such successful statesmen, having brokered a peace and reconciliation more than having won a war.

It was not to be, partly because of the conviction, shared by Franklin and Adams, that American independence was not hostage to the Continental Army.  “If the Enemy is beaten,” Franklin observed, “it will probably be decisive for them;  . . . But our growing Country can bear considerable Losses, and recover them, so that a Defeat on our part will not by any means occasion our giving up the Cause.”

The Treaty of Paris in 1783 formally acknowledged the American triumph at the siege of Yorktown in 1781. In the years that followed, there was much soul-searching in London to explain what happened. One current of thought, pushed by Germain and others, assumed that, had the Howes acted more aggressively in 1776 they would not only have destroyed the Continental Army — almost everyone agrees that they would have done so — but also that they would thereby have crushed the rebellion and ended the war.  Ellis acknowledges that we can never know for sure what would have happened.  But his book eloquently argues that “the balance of historical scholarship over the last forty years has made that a highly problematic assumption.” To win the war, Britain would not only need to destroy the American Army, it would also have to subjugate the American people as a whole. And that, as Franklin saw, was a task that not even all Europe could accomplish.

It’s a heartening but also a sobering thought. On this July 4, 2013, nearly a quarter of a millennium after the exploits Ellis recounts, it is worth recollecting and celebrating the spirit that, even more than Washington’s armies, made American independence possible.  It is also, in this era of bloated governmental intrusiveness upon the rights and liberties of citizens, worth pondering what future that spirit is likely to enjoy.  “Well, Doctor, what have we got — a Republic or a Monarchy?” someone asked Frnalin as he left the Constitutional Convention in 1787.  “A Republic,” replied Franklin, “If you can keep it.”  Can we?  I wish I felt more certain about the answer than I do.