POLITICIANS should think twice before sticking their oars in when it comes to sport. Apart, that is, from former North Korean supremo Kim Jong Il, who was clearly so handy at golf the first time he tried it that he set a record of 11 hole-in-ones in the same round.

As much capital as there can be to play political football, there are own goals to be scored too. Remember Tony Blair doing keepy-uppies with Kevin Keegan, David Cameron being unsure whether he supported West Ham and Aston Villa and Boris Johnson apparently being unsure whether he was playing football or rugby when he went to tackle an opponent during one charity match.

Displaying all of his typical lightness of touch, albeit in a far more serious matter, this is where President Donald Trump and the NFL anthem protest row comes in. This has been something of a slow burner, all kicked off by Colin Kaepernick, then a somewhat fading quarterback at the San Francisco 49ers, back in 2016. “[I’m] not going to stand up to show pride in a flag for a country that oppresses black people and people of color,” Kapernick said, after kneeling during the Star Spangled Banner in protest mainly about the number of killings of black suspects in police custody.

It is worth stating at this point that Trump and the NFL, of course, is a saga which goes way back. Back during the 1980s, the Manhattan-based real estate mogul had ownership of the New Jersey Generals in the fledgling United States Football League, but his real designs were on an NFL franchise, the ultimate feather in the cap for any aspiring businessman. But the league wouldn't play ball and Trump has borne a grudge ever since.

Now he is President, even if perhaps the most under-fire President in the long history of this office, something came along which Trump interpreted as an open goal. It was a combination of Black Lives Matter and Kaepernick's one-man campaign, all of which snowballed further when Michael Bennett, the Seattle Seahwaks defensive end, also chose to kneel during the anthem in recognition of being singled out and a gun placed against his head as he left a party in Las Vegas following the Conor McGregor-Floyd Mayweather superfight.

On a trip to Alabama, Trump called the protesters and sympathisers “sons of bitches” then threw a bit more kerosene on the flames. “Wouldn’t you love to see one of these NFL owners, when somebody disrespects our flag, to say, ‘Get that son of a bitch off the field right now. He is fired. He’s fired!"

His calculation was that the majority of all US-wide polling suggested the majority of citizens disagreed with kneeling during the anthem, even if the vast majority of America's black population – most of whom don't vote for him anyway – might disagree.

That is why, by the time last Sunday came around, the whole thing touched every corner of the country, with players, fans, and media men alike all forced to pick sides and consider how important the anthem was to them.

Various commentators attempted to make sense of it, saying it was about race, or the military, but in truth if anything fostered commonality of purpose and unity amongst this group of players it was Trump itself, and a shared distaste for his crude tactics.

The Pittsburgh Steelers stayed in the locker room for the anthem, with the exception of Alejandro Villanueva, a former Army Ranger, who stood in the mouth of the tunnel. While they were booed by the Chicago crowd when they came out, now we have millionaire owners such as Shahid Khan of the Jacksonville Jaguars, Arthur Blank of Atlanta or Jerry Jones of the Dallas Cowboys hunkering down pre-game alongside their players as a show of solidarity.

With the genie out of the bottle, this story could run and run, and it will be instructive to see how this week's games pan out, starting with a high profile, historic fixture between Chicago and Green Bay tonight. Like the equivalent of of a wildcat strike, other sports may soon follow suit.

They say politics and sport don't mix but when they do it can have powerful results. This episode, of course, has echoes of Tommie Smith and John Carlos' 'black power' salute at the 1968 Olympics, while Andy Flower and Henry Olonga wore black armbands to protest against Robert Mugabe's running of Zimbabwe. Nelson Mandela's appearance in a Springboks' jersey in the 1995 Rugby World Cup final was of totemic importance to South Africa's efforts to heal the wounds of apartheid. President or not, Donald Trump must be awfully sure of his calculations if he thinks he can take on sport and win.