Donald Trump needed a nudge before remembering to put his hand in the correct position during the national anthem. Many have fallen foul of this iron-clad rule of American life – but why is it so important?

Perhaps it was tired from all those weird gestures – or the golf, or the bombing – but it appeared for a moment as if Donald Trump’s hand had failed to go in the same direction as those belonging to his young son and the 7ft rabbit next to him – namely towards his heart.

Footage of the national anthem at the White House Easter egg roll on Monday suggests Melania comes to the rescue. She, too, remembers the drill and, with her other wrist, nudges Trump’s arm, which hangs limply by his side. It immediately springs up towards the First Ticker as the anthem reaches its second line. Disaster averted: Trump gets away with a few mocking tweets and incriminating gifs. But pity the prominent American who discovers that, in the land of the free, manual symbolism matters, big league.

Honouring the flag during the pledge of allegiance or anthem used to require more effort. The Bellamy salute, introduced in the 1890s to unite the US after civil war, involved raising a hand skywards, arm straight, palm down. Sounds a bit Nazi, doesn’t it? Which is why, when heiling Hitler got big, the 1942 US Flag Code required that civilian Americans place a hand on the heart instead. Doing so stopped being optional some time later.

So, it wasn’t enough that Gabby Douglas had sacrificed everything to win for her country as part of the US women’s gilded gymnastics team at last year’s Rio Olympics. No, the true test of patriotism was the position of her hand during the medal ceremony. It did not reach her heart, and the backlash traumatised the athlete, who also felt compelled to apologise.

Gabby Douglas says she did not mean 'disrespect' over US national anthem Read more

This gesture is so important that some have sought to unleash fake news of misdemeanours. After a Republican presidential debate in 2015, a photo circulated, credited to Reuters, showing Trump not raising his hand to his heart during the anthem while his rivals did so (incidentally, the picture also shows Ted Cruz getting even closer to his heart by slipping his hand inside his jacket, like a Poundshop Napoleon). However, as the excellent Snopes factchecking site showed, straight-armed Trump had been Photoshopped in from a different image; on that occasion he had remembered to raise his hand.

Of course, Barack Obama’s hands were frequently scrutinised. As a young senator, he failed to raise his hand during the anthem at an Iowa steak fry (egg rolls, steak fries – yep, US politics is weird). As president, he once saluted a marine while clutching a coffee cup as he stepped off his helicopter. Cue: OUTRAGE.

Trump has required prompting before. At his own inauguration concert, a band asked the crowd to “stand up if you love America”. Trump remained seated until he felt a now-familiar spousal nudge. Behind every great man and all that.