New Zealanders are entitled to know who and what they are voting for. Brash's leadership of the National Party was fumbling. But he was still the leader who struck a chord with voters sufficient to put the party back into the electoral race.
It may have been logical to Brash and Key that the younger politician would ultimately have been the successor after he had gained some ministerial experience.
But it doesn't make sense that Brash would simply hand over the reins after just a couple of years at the top unless he got something big in return.
This, after all, was a man who was prone to musing that Sir Winston Churchill was Prime Minister of Britain in his 80s. Being the nation's leader in his late 60s made him a mere stripling in comparison, Brash implied back then.
Both Brash and Key need to put a lot more on the table about this "deal". Key has equivocated in his public comments. In essence he has confirmed the pair met in the motel room. There had been discussions but nothing was formally agreed.
In fact, Brash wrote that the pair discussed the leadership on several occasions. The plan was for Brash to lead National to victory in 2005, for him to be prime minister and Key finance minister before handing the leadership to his anointed successor.
It's a moot point that Key, having entered politics himself with the aim of one day being prime minister, would have been miffed that Brash had built a bridgehead into the leadership ahead of him.
What's not addressed by Brash is what role he would have had after Key's ascension. It seems improbable he would have simply wanted to retire from the fray given that he later grabbed the chance to lead Act at the 2011 election.
In my view it is quite probable that Brash would have pushed to be minister of finance, a role that he was arguably more qualified for than Key in the first place.
This is evidenced by his willingness - still - to stand on principle for what he believes is right, such as raising the qualifying age of national superannuation, something Key will not address.
This is all in the realm of speculation now.
What is not a matter of speculation is the way Brash has been cast aside by former National colleagues who find him an embarrassment because he advocates some policies that their party would have stood for if they had not lost their courage in the MMP wash.
Incredible Luck is remarkable for its pathos and Brash's obvious tin ear.
When Key offered him a plum "kiss-off" role as High Commissioner to London after he left Parliament, he turned that down to make an absurd play for the Washington post that had already been earmarked for former World Trade Organisation head Mike Moore.
Key appointed him chairman of the 2025 Taskforce. Then promptly ignored its recommendations.
Brash still presents himself as the "anti-politician". But in truth he has always been a bit of a drama queen.
At the Reserve Bank he used to refer to himself in the third person. There is little deep coverage of the 14 years he spent wrestling with inflation and banking crises.
Brash's level of introspection is not incisive.
Friends like former Labour Cabinet minister Michael Bassett warned him off a political career.
Brash did not quickly conclude (nor has he yet) that politics was the one "ruthless mistress" he should have steered clear of. He had a fling or two. But apart from his relationship with Je Lan, who went on to be his second wife, none of these have gelled into long-term public relationships.
His succumbing to the seduction of politics also meant he cast aside a brilliant banking career for a vainglorious shot at political power.
What comes through is a man of ideas who still hankers for political influence. But by entering politics and then failing dismally at that particular art he gave up the very real influence he had from the outside.
