In essence, McCullum's holistic performances over the past seven weeks have mirrored what Martin Crowe achieved when he was named player of the tournament 23 years ago. McCullum must be a contender to receive the same honour, regardless of today's outcome. In another generation, when cricket buffs reflect on this tournament, his name will leap to mind as much for the direction he gave his team as anyone else's performance with bat or ball.
If he retired tomorrow, McCullum would leave a larger-than-life, mercurial legacy.
Hadlee's greatness is easily defined. He had a world record 431 test wickets by retirement, had been the linchpin in the 1980s golden era and brandished a knighthood in his final test.
McCullum's achievements are less based on statistics and more a gut feel as to the indelible influence he has had on his players and spectators.
The skipper probably needs another couple of years in the game, combined with test series wins away against England and home and away against Australia next summer to eclipse Hadlee. A World Cup win might change that.
McCullum has not only played well himself but those within the camp suggest that others have exceeded expectations of their worth and are richer for having worked with him. Literally for some, judging by their influx into tournaments like the Indian Premier League.
Rumours waft about McCullum considering retirement after the England series, or that he might hold on to reach 100 consecutive tests since his debut against South Africa in March 2004. No one has done that, although AB de Villiers has 98 compared to McCullum's 92. It's dependent on how much more punishment McCullum's frame can take. The 33-year-old already risks becoming Quasimodo in his retirement village, given the difficulties with his back.
McCullum shored up his test credentials with the highest New Zealand test score of 302, a couple of double centuries and a blistering 195 in Christchurch, combined with series wins over India, West Indies (home and away) and Pakistan.
His one-day batting has been showcased by the highest strike rate (192) of anyone to face more than 36 balls at this tournament. He made significant innings in four New Zealand wins against test nations with 65 off 49 against Sri Lanka, 77 off 25 against England, 50 off 24 against Australia and 59 off 26 against South Africa.
In some respects, that misses the point. McCullum's greatest contribution has been his leadership.
Strong performances have been coupled with a culture of humility. Nothing appears taken for granted. There is no sense of the entitlement which can inadvertently seep in with success. Take, for instance, a recent scene when a local net bowler was enjoying an outstanding spell against the New Zealanders at practice. McCullum's instinctive reaction was to offer congratulations and a friendly glove punch.
The controversy surrounding him securing the captaincy has been well-documented but since his horrific first test series loss to South Africa he has, in his preferred horse racing parlance, made most posts a winner.
His leadership with the bat has encouraged his players to up their strike rates, too - just look at Grant Elliott, Corey Anderson and Luke Ronchi. That was instrumental in helping New Zealand to achieve the highest run chase in World Cup knockout history with their 299 for six against South Africa in Tuesday's semifinal.
McCullum's relationship with his bowlers has brought the best out in Tim Southee, Trent Boult and even Daniel Vettori, whose 15 tournament wickets at 18.80 and an economy rate of 3.98 have been a revelation.
Setting four slips and a gully for Boult against Moeen Ali was the ultimate demonstration to other teams that he had explicit confidence in his attack. Likewise, catchers have been brought in liberally around the bat when wickets fall and during the powerplays. Batsmen obliged by tying themselves into bewildering mental knots.
In the field, McCullum has applied the same aggressive philosophy. Mitchell McClenaghan was hit over cover against Bangladesh and the captain tore after a certain boundary. He came off second best with a tournament sponsor. He was lauded on the one hand for his damn-the-torpedoes approach, on the other he plastered some tape and was lambasted for risking injury in a situation beyond reprieve.
The best New Zealand eras have coincided with exceptional captains who reflected the zeitgeist - the measured Walter Hadlee in 1949; the astute Geoff Howarth and cerebral Jeremy Coney of the 1980s; the street-wise Stephen Fleming heading into the 21st century. McCullum has joined, if not surpassed, their company, regardless of tonight's result.
Rarely have perceptions around a New Zealand sportsman generated such a spectrum of applause and derision. Across McCullum's career, opinion tended to be compartmentalised into phrases like 'brash maverick', 'cocky mercenary', 'generous benefactor' and 'loyal mate'.
Minimal evidence supports the former two guises other than confidence on the field and tattoos of his playing number and children's birthdates on his upper right arm and an ink band for a wedding ring. A former first-class wicketkeeper spoke of a club match where a youthful McCullum sledged from behind the stumps.
When it came McCullum's turn to bat, the senior gloveman repaid the favour by walking with him to the batting crease, taunting all the way. McCullum was barely affected as he propelled his side to victory. The veteran couldn't wait to shake his hand at the end after witnessing such a commanding display.
McCullum, like most sportspeople, has matured across his career to become one of the most respected and sincere New Zealand sportspeople. Today is the day he can tattoo his name into the cricketing annals forever.
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