The strategy behind the Prime Minister's endorsement of John Banks in Epsom is inexplicable. A week ago Mr Key appeared to be close to winning a majority for his party to govern on its own.
Now he has irrevocably yoked himself to the disgraced Act brand and told potential Act voters their vote might not be wasted, so they can switch from National if they want.
In return, National gets the corpse of a political party not worth saving, and associates itself with the views of Act and Mr Banks.
Instead of endorsing John Banks, the Prime Minister could have asked him what he meant when he said on TV3's show The Nation that the "root cause of law and order" is young Maori and "Polynesian" men in South Auckland being paid the dole to sit in front of TV watching pornography and smoking marijuana while they're planning to come through our windows.
Or when he said in North & South magazine in 1993 that gays "should not be put in charge of vulnerable young people".
Or his speech in Parliament when MPs decriminalised homosexuality, saying it was a "sad and sickening day for New Zealand", adding that "the family unit in New Zealand is under siege".
By endorsing the holder of these views, Mr Key has associated National with bigotry. He has also tied National to Mr Banks' record of trebling Auckland City's debt as mayor, a record of fiscal impoverishment matched only by the deterioration of the Government's finances in the past three years.
Now Mr Key is refusing to discuss what he said on the tea party tape. Reporters have asked him if he sniggered that Winston Peters' supporters are all dying out; they've asked him if the pair discussed removing Don Brash as Act leader as soon as the votes were counted.
If Mr Key claims he didn't make these statements, the tapes will be released because it's in the public interest to know when a politician says one thing in public and another in private. So he's keeping his trap shut in a silent confirmation. Therefore Mr Key planned his high-profile invitation to vote Act at the same moment he was discussing removing the leader of Act.
Voters should choose the representative they most want. Instead, the circus in Epsom has been motivated by the interests of politicians.
One theory about last Friday's tea party was that National was getting frustrated about continued speculation over Epsom. The thinking was that it's better to get the event out of the way early.
But the tape fiasco has kicked the story for another week. The tape should never have been made, but it goes too far to play the victim as Mr Key has.
In 1989, a reporter accidentally recorded Sir Geoffrey Palmer's press secretary telling him off over his media performance. A couple of years ago, then Labour Cabinet minister John Tamihere called the management of Labour "front bums" and sprayed insults on tape when he thought an interview had ended.
National used those conversations to taunt opponents. So having been happy to use wrongly recorded conversations in the past, our sympathy can be restrained at finding Mr Key has been caught on tape at a photo opportunity he organised, and with media standing only metres away.
The tape is a sideshow. Its content is a democratic abuse that would best be repaired by voters of Epsom choosing the electorate representative they most support.
John Pagani is a former adviser to Labour leader Phil Goff and former Progressives MP Jim Anderton. He blogs at johnpagani.posterous.com.