On July 4, the night sky over the Hudson Valley was clear and empty. No planes, no mist, no rain, allowing fireworks to explode with spectacular brilliance. Above the towns, the whoosh and bang sounded out something more than the usual burst of patriotic glee: the soundtrack of relief, the sense of Covid in retreat, if not yet defeated. At home, after the oohs and ahs, a miniature percussion section (our three small grandsons) marched up and down the back deck to the strains of Sousa’s “Stars and Stripes Forever”, putting their all into saucepan-lid banging in time with the beat.

Absent from our family celebration — only because it’s currently in London storage — is an enormous, slightly moth-eaten 19th-century Union Jack. I’ve been known to hang it on July 4, not as a gesture of British party-pooping or to aggravate the neighbours, but because this particular neck of the woods has a fascinatingly mixed history as a theatre of the Revolutionary War.

The country around here, like all of America during the revolution, was divided into equally numbered thirds: Patriot, Loyalist and nervous neutrals. Across the river and a little way upstream, the improvised fort (actually earthworks) at Stony Point was established by the British general Clinton to control the Hudson, but was taken in a daring attack by “Mad” Anthony Wayne’s force of American commandos on July 16 1779.

Closer to home, at Tarrytown, the British spy Major John André was caught, before he could reach Benedict Arnold at West Point. Documents André was carrying revealed the plan to deliver the fort to the British army and, to George Washington’s incredulous horror, the perfidy of one of his most trusted generals.

Flags — these days, the rags of polemical rage — also have a mixed history. In 1929, the dashing aviator Opal Kunz dropped a mass of them from her plane directly over the site of the battle of Stony Point. Those were the “Betsy Ross” flags created by the eponymous Patriot upholsterer, featuring red and white stripes but with the five-pointed stars of the 13 colonies arranged in a circle to symbolise, optimistically, perpetual union.

But the Betsy Ross was preceded by the Grand Union Flag, designed by the Philadelphia milliner Margaret Manny for the new fleet of the American navy. Manny’s flag had the obligatory stripes but, in place of stars, the top left canton featured the Union Jack.

But then history is a great mischief-maker, the enemy of simplicities, especially those of national allegiance. “The Star-Spangled Banner” was adopted as the American national anthem only in 1931. Prior to that, “America (My Country ’Tis of Thee)”, first performed on July 4 1831, served as patriotic hymn along with “Hail Columbia”.

Confusingly, its melody is that of the British national anthem. Which was, in fact, the point. The last line of the hymn of monarchist devotion is replaced by an American democratic alternative: “let freedom ring” supersedes “God save the king”.

But one artful contrafactum brought on another. In 1843, AG Duncan wrote a stinging, abolitionist version which begins:

My country ’tis of thee / Stronghold of slavery / Of thee I sing

The second verse is even more to the point:

My native country, thee, / Where all men are born free, / If white’s their skin

The jarring discrepancy between the “self-evident” truth of human equality asserted in the Declaration of Independence and the brutal reality of America’s founding being built on the backs of the enslaved is not, then, some contemporary piety of the “woke”. Since Samuel Johnson acidly inquired “How is it that we hear the loudest yelps of liberty among the drivers of negroes?”, this founding contradiction has never been out of view.