James Lawton: A decision that could make Capello. Even if it does break Green

Algeria may provide lightweight opposition here tonight but the burden England, and especially their leader Fabio Capello, carry is heavy enough.

It is to disprove the belief that they are a team who have lost their way, shed all the certainties imposed so encouragingly by Capello when he took charge two years ago.

This makes it by far the most acute test of the huge and perfectly justified reputation of the coach since he took office for the first time on the international stage.

The challenge, it has surely been evident from the moment of Robert Green's personal catastrophe in Rustenburg six days ago, is to resolve a single question: who plays in goal?

There are other issues concerning who partners John Terry in the absence of Rio Ferdinand and Ledley King, who plays alongside, if anyone, Wayne Rooney, and whether there should be a place for the coiled, frustrated ambition of Joe Cole.

The answers, it seems here, are Michael Dawson, Steven Gerrard, on Rooney's shoulder, and yes, Cole has the nous and touch to sharpen the English cause.

But if these are important details, they are still details and they pale against the requirement tonight for the momentum provided by a coach more concerned with one overriding principle than a set of successful balancing tricks. The belief that needs to be exerted, more than anything on behalf of the authority and effectiveness of Capello, is that performance and confidence is everything.

Apparently the most popular belief is that having decided, with obvious agony, that Green was the best of three much less than overwhelming candidates, Capello is obliged to stick with that decision as though it was carved from stone.

It wasn't. It was a desperate compromise – everyone in football knew that – and not some open-ended commitment. This isn't to be callous about the predicament of Green, a professional of obvious character. He earns his living in a perilous business and faces the risks implied every time he goes on to the field. If he was an accountant who had made a slip of the pen, his boss could afford to ask him to be a little bit more careful next time. But as someone whose stock in trade is the creating of confidence in his team-mates, Green must surely know that in the middle of a World Cup there is not much room for such generosity.

The issue is not Green's career, important though that is to him after all the hard work he has put in, but the well-being and self-belief of England and the continuing professional prestige of their coach.

A large part of Capello's reputation has built around the assumption that he is utterly hard-nosed. He underlined that when he stripped the captaincy from John Terry, not out of any bogus sense of morality but the reality that the Chelsea man had brought a series of heavy distractions to the business of running a well-ordered team. He did it again when he decided that Theo Walcott had not done enough to deserve his ticket to South Africa.

Walcott was devastated quite as much as Green might be tonight if he learns that he is to pay the price of the error which cost England victory at the start of the World Cup effort. But did Capello linger over Walcott's distress or the shattered assumption of Terry that he could make his own rules? If he did, it could have been no longer than it took to impose the verdict, which in Terry's case was a matter of minutes and in Walcott's less.

What if young Joe Hart, a player in good form, was to make a similar error against Algeria or some other team along the way, we are asked. Imagine the pressure, we are told. But Hart has not made that error, not yet, Green has, and Capello is now expected not to draw a line between the facts. If he gets the call Hart will feel the huge pressures that come to everyone performing the loneliest job in football, but he will not be obliged to live with the undermining reality that for nearly a week now his mistake has been a matter of fierce national conjecture.

We have reports that the England team which, but for Frank Lampard, reacted to Green's mistake not with immediate compassion but plain horror, is now restored in their belief in the goalkeeper. This may or may not be true, but it doesn't touch the duty of the coach to make a decision stripped of sentiment and any neglect of the obvious psychological implications of sending out a goalkeeper suffering from an open wound. If Capello is true to the instincts of the hardest, and most successful practitioners, of his trade he is unlikely to step back from this responsibility.

Sir Alf Ramsey discarded Jimmy Armfield, an England captain of much class, because of one defensive mistake which, in the coach's eyes, revealed a potential fault line in his plan to win the World Cup. Capello has been compared to Ramsey more closely than any of his predecessors.

Tonight we may see some compelling evidence to support the claim. It would come with the appearance of Joe Hart.