George Dobell is a senior correspondent at ESPNcricinfo
Just as it is remarkable how a player can make the journey from 'promising' to 'has been' in the blink of an eye, so a team that looked as if it was rebuilding nicely can suddenly be reduced to rubble.
Just three months ago, after they had won Test series against West Indies and South Africa, England were looking forward to this Ashes tour with realistic if guarded optimism. While their squad had some obvious flaws - not least the reliability of the top-order batting, a lack of pace bowling and the on-going issues over spin - it was also given depth by the presence of several allrounders who offered the chance to rebuild with the bat and spread the burden with the ball. They weren't favourites, but they had a decent chance.
Now, as the mushroom cloud from the Ben Stokes affair continues to fall, it seems this England team are coming to a precipice. If England lose the WACA Test - and it bears repeating they have lost their last seven Tests in Australia and their last seven on this ground - the series will be gone and the possibility of a whitewash will rear into view. As a result, there will be scrutiny on both the management - the coaches, the selectors and all those who appoint them - as well as the players. History suggests that someone - maybe several people - will pay with their jobs.
So while we become accustomed to hyperbole before games - they're all huge or massive or big and sometimes all three - when Joe Root said England were playing "one of the biggest games of our lives" this week, he was probably spot on.
If England lose, there will be greater reflection on the culture of the team and questions asked about the management style of the coach and the England director. Have the players been given too much leniency and is a firmer hand required? Have England's Test results improved since Trevor Bayliss was appointed, or might all involved be better served if he concentrated on the white-ball sides? If England lose, both Bayliss and Andrew Strauss will, rightly or wrongly, be left in uneasy positions.
If England lose, there will be questions asked about selection. Why was James Vince, for example, recalled to bat at No. 3 despite a County Championship batting average of 32.94 in 2017? What was the experiment with Liam Dawson about and why was Adil Rashid discarded despite the wickets he took in India a year ago? If England lose, James Whitaker will, rightly or wrongly, be left in an uneasy position.
If England lose, there will be questions asked about whether it is time to invest in younger players. The likes of James Anderson, Stuart Broad and Alastair Cook will all come under scrutiny as questions are asked whether the time has come to make a change ahead of the next Ashes series in 2019. There will be an immediate pressure to bring in new players. We already know that Mark Wood will join the squad for the final two Tests, but the likes of Joe Clarke, Liam Livingstone and Dan Lawrence - all in Perth as members of the England Lions squad - could also be added to the party. If England lose, several of this squad will, rightly or wrongly, be left in uneasy positions.
Meanwhile, there will be a focus on the county system and the success of the performance centre at Loughborough. Coaches and managers involved will come under greater scrutiny. Why is that England are not producing more fast bowlers - or fit ones, anyway - or potent spinners? Why has it taken so long to find a new opening pair after the retirement of Strauss? If England lose, the likes of Kevin Shine (lead fast bowling coach) and Peter Such (the ECB's spin bowling coach) will, rightly or wrongly, be left in uneasy positions.
There may be further reflection on Stokes, too. Views around the England squad may well have hardened towards Stokes in recent days. While there is still fondness for him as a man and respect for him as a cricketer, there are a few who are only now realising how their own lifestyle has been impacted by that incident. There might well be some resentment. If England lose Stokes will, rightly or wrongly, be held partially accountable.
And England will suddenly be, whether for better or worse, at the start of a new rebuilding phase. And that means change, lots of it.
The good news - for England at least - is that they can win. They are certainly not favourites, but the margins between these sides are nothing compared to those in 2013-14 and this surface, once so full of pace and fury, has settled into a more sedate dotage. The Australia team is good, but there's nothing to fear there.
In an attempt to close the gap between the side, the England management have decided to make a minor tinker to their batting order. Jonny Bairstow will move back to No. 6, with Moeen Ali returning to No. 7 to ensure there are not left-handers at No. 5 (Dawid Malan) and No. 6. While it does seem fair to ask why they couldn't have envisaged that problem at the start of the series, it is also probably fair to accept that few could have predicted the extent to which Nathan Lyon should trouble them.
Olly Stone was among those at England training on Wednesday. Stone, like Jamie Overton, George Garton, Josh Tongue and Zak Chappell, is the sort of pace bowler who might make a difference the next time England make this trip. If the ECB can find a way to ensure they play enough cricket to develop while not compromising their pace or their fitness, England will have greater firepower next time.
But if England lose at the WACA, the future will be a lot closer than many of those involved currently think.