"Why," he says, "would I work so hard for four years as captain, put up with so many sleepless nights, lose half my barnet, only to feel disappointed when we achieve what I always wanted us to achieve?"
It's well put and I have no reason to doubt him. Yet I don't think it's entirely fanciful, with the image of England's tired cricketers milling about Tony Blair's back garden fresh in the mind, to compare Hussain's situation on Tuesday with that of Neil Kinnock on the day after Labour's election victory in 1997. The parallels are striking: it had been 18 years since England won the Ashes; it was 18 years since Labour were last in power. Hussain's job, like Kinnock's, was to lift an ailing institution off the floor, but in the moment of ultimate triumph, he was a bystander. Could Blair have won had Kinnock not put in the spadework? Probably not. And yet the change of leadership (with apologies for airbrushing John Smith out of history) was necessary. So, for Blair read Vaughan, for Kinnock read Hussain.
I don't know what Hussain's politics are but something in those dancing green eyes tells me to spare him my theory. We meet first at the Oval, on the second day of the final Test, and then I talk to him again when the whole extraordinary business is over. The turning point in the Ashes, he suggests, came at Edgbaston even before play began.
Glenn McGrath turning his ankle on a stray cricket ball, followed by Ricky Ponting inexplicably inserting England on a good batting wicket, was the double whammy which turned the series in the home team's favour. Not, he adds, that McGrath's injury should detract from England's achievement.
"It's not like we haven't had injuries ourselves in the past, and to Simon Jones in this series," he says. "And the boys still had it to do. But thanks to those two things, McGrath's injury and Ponting's decision, they were able to implement an aggressive game plan, scoring at five an over."
It is 18 months since Hussain had to start getting his tongue round "they" rather than "we" when referring to England. The "we" is now Sky, which puts him in an invidious position when people bang on, as they have been doing this week, about the "scandal" of Test cricket being lost to terrestrial television. It is a subject he would rather avoid; equally, it is one on which I am eager to hear his opinion.
"The bottom line is that you cannot doubt Sky's commitment to cricket or sport generally," he says, just a little shirtily. "You need to look at the other broadcasters, who didn't bid at all, or didn't bid enough. I can't believe some of the criticism Sky has been getting. Sky were on board in 1989/90, when I went to the West Indies on my first tour, providing ball-by-ball commentary. I'm on my way right now to cover a County Championship game (Kent v Nottinghamshire). And Sky also covers women's cricket, Under-19s cricket ..."
Which is admirable, of course, and he is quite right to defend his employers to the hilt, but the painful fact remains that a large proportion of the population will no longer be able to watch live coverage of Test cricket. "They can," says Hussain. "If sport is that important to them they can go and buy a bloody dish."
It is, in fairness, a comment made off the cuff and on the motorway, and for what it's worth I agree with him that the debate about Test cricket's television future is shrouded in sanctimony. Sky should really not be the target of anyone's ire, although the same cannot necessarily be said of the England and Wales Cricket Board, the Government, the BBC, even Channel 4.
Whatever, for those of us with access to Sky, Hussain has been an impressive addition to the commentary box these past 18 months, talking articulately and sometimes forensically about the game when next to him the likes of Ian Botham and Bob Willis are inclined to deal in platitudes.
Botham, of course, was one of his chief tormentors when he was the England captain, but he insists, a tad disingenuously, that there was never any ill-feeling.
"I've always got on well with 'Beefy'. When I was captain I was often round his room having a glass of wine. But Beefy makes comments, and I used those comments to spur me on. You can't argue with him because he's a legend, but when he said it was time for me to go, or that I couldn't bat at No 3, I put those things in my cricket bag and got them out when I needed them. We banter about it now. He asks me how many Ashes series I won, I ask him how many hundreds he made against the West Indies."
Hussain now has another weapon in his arsenal of put-downs; he can ask Botham what contribution he made to England's greatest Ashes victory of all time. His own contribution, meanwhile, should not be overlooked. Yet he says that there was not a single moment this summer when he yearned to be out there. Surely the competitive fire still burns?
"Not really. I have a young family who give me more pleasure than cricket ever did, and I can put things behind me now. At Sunningdale the other day, playing golf with [Michael] Atherton against [David] Lloyd and [Paul] Allott, I missed a 10ft putt on the last green to halve the match. I sank to my knees and whacked the turf, but if it was cricket I would still be thinking about it. I still think about that World Cup match, Australia 100 for 8 chasing 180 and Bichel and Bevan saw them home. How did we not win that? I'll think about it for ever. There are still enough cricketing thoughts for me to get fiery about. But I knew 18 months ago that my time was up.
"The reason I left when I did was because I didn't want to feel in any way bitter or twisted towards the game. I see too many cricketers hang in there, and then get left out or axed, to a degree like the Graham Thorpe situation this summer. There was a bit of tension between him and [chairman of selectors] David Graveney and I never wanted anything like that. I had my period, 96 Tests over 15 years, and I felt it was important that I left with some dignity."
His last match as an England player contained dignity in the form of an undefeated century, which helped beat New Zealand by seven wickets. He had resigned the captaincy the previous July, after the first Test against South Africa.
"I could see that we now had a young side who needed to go out and express themselves, who needed - it sounds a bit American - to be set free.
"They didn't need me cracking the whip any more. It wasn't the Caddicks, the Goughs, the Stewarts, it was Flintoff, Harmison, Trescothick; and Michael Vaughan was the best man by a long way to lead them. But at the same time this whole Hussain-Vaughan thing ... I was supposed to be this tough leader, always having a go at the players, but there were a lot of arms round shoulders, a lot of knocking on hotel-room doors, seeing how the players were, trying to get the best out of Caddick, out of Gough. What you saw wasn't necessarily what you got and it's the same with Vaughan, except vice versa. You see this relaxed, David Gower-type captain, lots of smiles and kisses and hugs and cuddles, when actually behind the scenes he can be very tough. Like me, he's very fortunate as captain to have two things: central contracts and Duncan Fletcher, one of the great men of cricket."
There aren't many - make that any - broadcasters who know England's lugubrious coach as well as Hussain does, another reason why he is a valuable commodity in the commentary box.
"The biggest thing for Fletcher is loyalty," he says. "Even now, Vaughny will still hear rumblings in the hotel bar. 'We're training too much, why are we getting up so early?' And it's very easy after a couple of rum and Cokes to slip and say, 'Yeah, bloody Fletcher, I'll have a word with him'. But you have to be loyal. You have to say, 'Hold on, half eight on the bus means half eight on the bus, you be sure you're there, mate'.
"Having said that, I wouldn't eat out with Fletcher every night, a) because he's a boring git and you have to pay for yourself, but b) because you don't want an us-and-them mentality to develop. As captain and coach a lot of things should be done behind closed doors, because there's insecurity even in a successful side. Ian Bell will now be looking at Vaughan, Fletcher, Graveney, thinking, 'Are they talking about me?' And I've got huge respect for Keith Fletcher at Essex, but there was a time when he almost got a little too close to Ronnie Irani, the captain. The captain and the coach should be close, but the captain has to feel like he's one of the team, and it's even more important that the team feel he's one of them. [Duncan] Fletcher encourages that, and he understands the mentality of players. He doesn't hand out bollockings, there are no naughty-boy nets, no Alex Ferguson teacup throwing, but when he does raise his voice, on that one occasion a year when he does get cross with someone, you listen. He also knows that meetings just for the sake of them don't work. If there's a meeting every day then by June someone like Flintoff will be switched off."
Ah, Flintoff. Hussain has watched with great pleasure the process by which the big man has turned himself into one of the world's truly great cricketers. "And he really has done it himself. He used to rely just on his talent, but now he puts in the hours off the field, and it's not just that his fitness is better, it's what it has done to his mindset. It's like you doing preparation for this interview. It's not just that you've done the homework, it's the confidence it gives you knowing you're prepared. It's the same with Freddie."
But even a confident Flintoff firing on all cylinders needed support, and he got it, magnificently, from the rest of the bowling attack. Hussain points out that Fletcher's strategies for targeting the Aussie batsmen were largely the same as they had been in the previous Ashes series; but this time they were deployed properly.
"Last time, the bowlers would deliver three out of six balls in the right area; this time it was five out of six. That makes a huge difference in keeping [Adam] Gilchrist quiet, keeping [Matthew] Hayden quiet. There was no let-up, and Simon Jones was the final piece in the jigsaw. Some people have doubted him, but Fletcher always knew that he would come good."
England's next task is to come good in Pakistan, which isn't far behind regaining the Ashes as the hardest challenge of all. Hussain's team did it, but Vaughan's team, he suggests, will have to do it differently.
"My mentality on the sub-continent was to sit in. I know how passionate the fans are, how much they want to see Inzamam or [Sachin] Tendulkar hitting boundaries, so my plan was to dry them up. If you think we're under pressure as England captains, it's nothing to the pressure on Moin Khan or Sourav Ganguly, whose houses get stoned if they lose a Test series. So I knew in Pakistan that if we got them to the last day of the series they'd be under huge pressure, and sure enough we nicked it on the last evening, just by transferring the pressure from us to them.
"This team will approach it differently, but it will still be maybe the hardest cricket they'll ever come across because conditions are so alien on and off the field. The important thing is not to go out with a siege mentality. It's easy to moan about the food, the heat, the pitches, the umpires, service in restaurants. The trick is to enjoy the culture and stick together. Knowing them, sticking together won't be a problem."
He smiles. It is the smile of a contented man.
Nasser Hussain: Life and times of an England captain
* Nasser Hussain was born in Madras, India, on 28 March 1968, but grew up in Essex. His dad was a keen cricketer. In 1980 he became the youngest player to represent Essex Under-15s, aged just 12.
* Made his full Essex debut in 1987 and was named Young Cricketer of the Year by the Cricket Writers' Club in 1989.
* Makes England debut in 1990. Appointed Essex vice-captain in 1996. Promoted to captain in April 1999. Made England captain that July.
* Awarded the OBE in 2001 and the Wisden Cricketer of the Year award in 2003.
* England debut: v West Indies (Feb 1990) at Kingston, Jamaica.
England win by nine wickets.
* Final England appearance: v New Zealand (May 2004) at Lord's. Hussain makes 34 and 103 not out as England win.