How good is Wayne Rooney? How strong is his playing mentality when it really matters? Can he justify all the drum rolls accompanying his return to international football in Donetsk after an incident so crude, so bereft of responsibility, it still has the brute force to make you recoil?
The first question is the easiest because, of course, he is very good indeed but over the years he has made the other two more complicated – and never more relevant to the image of English football and its eroded reputation for producing not only world-class players but one who might take hold of this tournament Rooney joins so belatedly and under such a weight of expectation.
Again there can be a positive response – but only if his head is right, or certainly in immeasurably better shape than it was two years ago in South Africa. Then, yes, it is possible to imagine a significant, even sensational impact, but we cannot know until the platitudes he uttered in Krakow yesterday are replaced by the imperative of serious action.
Undoubtedly he is the best home product since Paul Gascoigne, the most naturally talented, the most intuitive. Unfortunately, under pressure he has also revealed a fault line almost as broad.
The comparison was touched on just six months ago by Sir Alex Ferguson when he felt obliged to fine Rooney £200,000, drop him from a Premier League match and then yank him from the next one with body language cold enough to register freezing point.
Rooney's latest England manager, Roy Hodgson, who in so many respects has yet to put a foot wrong, can only hope that his own serial warmth while anticipating the player's return against Ukraine has a similar effect.
Rooney has been remarkably consistent since that Christmas crisis at Old Trafford when Ryan Giggs told a meeting of players that he had never known a time when commitment and discipline had fallen so low in the United dressing-room.
No one reacted more dramatically than a Rooney who had already been reminded by Ferguson of the disintegration of that Gazza promise. Rooney relaunched himself with a brilliant goal at Manchester City and then kissed the club badge quite fervently. It seemed less a celebration and more an act of public atonement.
Inevitably it makes you wonder if there will be a similar gesture involving the Three Lions.
Hodgson has certainly put such a prospect at the top of his wish list – understandably enough when you consider the unevenness of the win over Sweden last Friday night and the manager's desire for a place in the quarter-finals with something more than the status of sacrificial victims if the opponents, as seems likely, are Spain. However you look at it, this is immense pressure on a player whose temperament has so often failed to match his instinct and his ability to play some great football.
There is neither space nor time to dwell on the accumulated disappointments that have followed Rooney's stunning arrival in the Premier League for Everton, his prodigious landfall at Old Trafford and, more than anything, his superb emergence as an 18-year-old in this tournament in Portugal eight years ago.
The closer parallel to his current situation was his injury-delayed arrival at the German World Cup, when he arrived trailing – perhaps impractically, given the extent of his physical problem – the promise of deliverance and left in a cloud of red mist.
Two years ago in South Africa there was similar expectation. After his injury late in the season against Munich, the Sun announced that the nation could breathe again because Rooney would be getting on the plane. It was hardly a solitary effusion.
The feeling here was that Rooney had stepped out of the shadow of Cristiano Ronaldo and was indeed ready to join the serious players at the great stage. Yes, why not, he could stand in the company of Iniesta and Xavi, Messi, Ronaldo and the Champions League master craftsman, Wesley Sneijder.
He was an authentic force of football nature, one of the last of the street footballers who had come to his moment. It seemed a reasonable point to make at the time, given Rooney's riot of scoring and self-belief before injuring an ankle in the spring.
Yet what we saw was the nadir of Rooney's international career. On the field he was near anonymous. He was a joyless, cantankerous figure throughout the tournament.
Now he tells us that he is thrilled to be back in the arena from which he banished himself so thoughtlessly and of course the nation – or least that part of it still prepared to make the emotional investment – is anxious to believe.
In this quarter the inclination has always been to believe. The level of ability is so high, the scale of his game can reach such heights. He came into the celebrity club of the "golden generation" with a range of talent that anyone could see. It wasn't to be hyped but simply recognised.
Always he gives some reason to renew the belief. In the 2011 Champions League final at Wembley, at the end of a season in which he had mixed brilliance and flashes of indiscipline remarkable even by his own standards, he was the only United player who didn't look somewhat out of place. He scored a goal of thundering defiance before the latest envelopment by Lionel Messi, Iniesta and Xavi.
After that game Rooney made a statement that still lingers in the mind far more powerfully than any wiseacre tweet or re-fashioned hair transplant. It was a tribute to the meaning of Messi and the obligation every professional had to follow as far as they could in the footsteps of the world's greatest footballer.
Rooney pledged himself to such an ambition. It was a high one, indeed, but hardly impertinent on the lips of such a gifted player. The hope is that he remembers it when the drums stop rolling in Donetsk tomorrow night.