Thousands of football fans gathered Monday night to attend the College Football Playoff National Championship game in Atlanta, Georgia, to witness the match between the Alabama Crimson Tide and Georgia Bulldogs.
But as The Star-Spangled Banner began to play, social media users turned their attention to his anthem etiquette.
Trump supporters backed him for standing upright, hand over heart and looking proud as punch.
He certainly didn't sing all of them.
"Wouldn't you love to see one of these National Football League owners, when somebody disrespects our flag, to say, 'Get that son of a bitch off the field right now, he's fired?'" Trump said in August.
Cameras panning to POTUS - who last week called himself "a very stable genius" and "like, very smart" - caught him appearing to momentarily flub the words to his country's most iconic song. But, technically, the president didn't break any rules by not singing the anthem.
People have accused the USA president of forgetting the words.More news: Donald Trump Screw Claims of Mental Instability 'I'm a Genius!'
By contrast, his predecessor President Barack Obama famously neglected to put his hand over his heart during the 2008 election campaign. Those in military uniform should salute.
It makes no mention of whether the anthem should be sung.
He was escorted onto the field for the "Star-Spangled Banner". In 1942 the National Anthem Committee wrote that "it is of paramount importance that emphasis be placed upon the singing of the National Anthem". Just show some respect for your country.
"There's plenty of space for people to express their views and to protest, but we love our flag and we love our anthem, and we want to keep it that way", he said. "He's fired. He's fired!'" Trump said at the time.
It is also pertinent to mention Trump pushed the national anthem as a partisan issue shortly before the game during a speech to the American Farm Bureau Federation in Tennessee, tweeting, "We want our flag respected - and we want our NATIONAL ANTHEM respected also!"
Later, Trump took to Twitter praising Pence for leaving the game. He also repeated his criticism of the NFL players who kneel during the national anthem in protest of police brutality and racial inequality.