How did it all come to this? Two grown adults squabbling in thinly-veiled public soundbites at a time when the people they represent need them now, more than ever, to sort out their act and get on with performing in the best interests of Manchester United.Paul Pogba and Jose Mourinho. “Oil and water” was how Sir Alex Ferguson likened his relationship with Pogba’s agent Mino Raiola ahead of the Frenchman’s initial departure from Old Trafford as a 19-year-old in 2012, and the same term might well be used for the differences between Pogba and his current manager as the rift between them grows every day.The list of issues is as long as one’s arm, with Mourinho publicly chastising Pogba for his failure to win a header against Newcastle and then picking Scott McTominay ahead of him for the Champions League tie against Sevilla. Editors’ Picks Man Utd ready to spend big on Sancho and Haaland in January Who is Marcus Thuram? Lilian’s son who is top of the Bundesliga with Borussia Monchengladbach Brazil, beware! Messi and Argentina out for revenge after Copa controversy Best player in MLS? Zlatan wasn’t even the best player in LA! Then there’s Pogba refusing time and again to commit his future to United when questioned during World Cup duty. Mourinho responded by suggesting Pogba’s summer success with France and relative failure with United was due to a short attention span in longer seasons.And that was all even before this season started!The last seven weeks has been one tedious saga after another, with the latest issues resulting in Mourinho telling Pogba he will never again captain United despite having recently served as vice-skipper, and on Wednesday there followed footage of a heated exchange on the training ground after the manager greeted his exuberant midfielder with a message which managed to immediately alter the player’s mood.Whatever their clear disdain for each other – because, let’s face it, this is more than mere dislike right now – there has to be some sort of resolution in the name of progress for the club. And however you look at the present situation, the biggest loser right now is Manchester United.Already eight points adrift on the Premier League ladder and having been this week dumped out of the Carabao Cup by Derby, the last thing the club needs is for this nonsense to continue. But what is the answer?Plainly put, if the two cannot grow up and work out their issues, then at least one of them has to go. And Pogba arguably should be the first out of the door as things stand.The 25-year-old, normally known for shunning many an invitation to speak to the press, has taken glee from stopping in the mixed zone on numerous occasions already this season as he seeks opportunities to stick the knife in.“There are things that I cannot say otherwise I will get fined,” is Pogba attempting to make a point of the fact all is not well. “I am not the manager, I cannot, like, say that, but obviously we should show more options of playing,” is not the rhetoric of somebody working for the group cause.Right now, Pogba couldn’t be doing a better job of alienating himself among the United fan base if he tried. But then the suggestion that he is attempting to do exactly that is not beyond the question either, as repeated talk of interest from Barcelona, Juventus and Paris Saint-Germain will always pique the curiosity of Raiola. And when the super-agent sniffs a great deal for himself and his players, he rarely loses the scent.For as long as Pogba is taking every opportunity to land a snide counter-blow every time Mourinho opens his mouth, there is no hope of anything but open warfare between the two. And if the club are to maintain a grip on the runaway power that players have to dictate the course of the organisation’s destiny whenever the whim takes them, they need to side with their manager and make a statement.If United had backed players over the manager every time Ferguson had a run-in with one of his stars, the great Scot could have been sacked a million times over and the club would likely have come nowhere near the success they achieved. The likes of Ryan Giggs, Lee Sharpe, David Beckham, Roy Keane, Wayne Rooney and many others would all have had their United careers curtailed long before they eventually moved on.But all of that is not to say that Mourinho is untouchable. Fundamentally, it is results which should always dictate a manager’s job security and, quite simply, United’s form is hardly helping the Portuguese’s case.There is every possibility that Mourinho could outlast Pogba at Old Trafford only to remain a sitting duck thanks to his inability to get the best out of this squad. Sure, the group ought to have been strengthened further in the summer, but the players he has are still massively underperforming and he has to sort that sooner rather than later.It should not be the Pogba war which brings about the end of Mourinho’s tenure, but it could end up helping to be a deciding factor nonetheless. Should January arrive with the manager encouraging the board to allow Pogba to leave in a bid to allow everyone to move on there are two scenarios which would potentially come into play.If United are flying and back in with a shout of Champions League football and potentially even an outside interest in the title race, then Mourinho’s words will carry some gravitas. In those circumstances, a petition to sell Pogba might be agreed upon by executive vice-chair Ed Woodward and the board.But should they continue their struggles through the autumn, by the time the transfer window comes around what board of directors is going to be convinced to sell their biggest playing asset by a manager whose own future would be very much up in the air? Flog potentially your best player because a dead man walking asks you to? Doubtful.As such, United’s results over the next three months become monumental for Mourinho. Not just because he needs to get his side back into a position of strength but also because on a personal level he must regain a position of true power when it comes to the club’s decision-makers choosing between him and Pogba.But even if he sees the back of Pogba, the chances of Mourinho lasting much longer than the Frenchman appear narrow given the current state of affairs. Because this story is oh so typically Jose Mourinho.Whether it is Iker Casillas, Eva Carneiro, Henrikh Mkhitaryan, Luke Shaw, Anthony Martial or Paul Pogba, it appears that Mourinho always has to be grappling with somebody to take the attention away from the graver issues beneath the surface.Selling Pogba would not mark the end of the problems, and nor would siding with the player and sacking the manager.With a player looking to undermine his manager and a manager picking fights wherever he can, United’s best resolution might well be to find exit strategies for the pair of them.But until that time comes, the only thing that can be guaranteed is that the fireworks will continue behind the microphones around Old Trafford way. Check out Goal’s Premier League 2019-20 fantasy football podcast for game tips, debate and rivalries.