The "et tu, Brutē" trick is one of the oldest moves in the political playbook but few people are as willing to play it as former National Party leader and Prime Minister Jim Bolger.
Bolger was on Tuesday announced as the head of a team of 10 people from the unions, business and work groups charged with bringing Labour's policy to set "fair pay" agreements to life.
It is a major shakeup of industrial relations and a policy National strongly opposes and has set as one of its key battlegrounds.
In Shakespeare's Julius Caesar, Caesar infamously says "et tu Brutē?" when he finds Brutus had betrayed him.
This is Bolger's third strike in terms of cuckolding National.
His first was signing up as Chair of NZ Post and KiwiBank under the former Labour Government.
His second was signing up as chair of KiwiRail following Labour's buy-back of it. It was Bolger who had privatised KiwiRail's predecessor New Zealand Rail in the first place.
Today he stood there again, shameless, on the stage of the Beehive theatrette alongside Workplace Relations Minister Iain Lees-Galloway.
He didn't even flinch when Lees-Galloway used the word "collaborate" to describe Bolger's involvement.
In his opening blurb, Bolger spoke of being shoulder-tapped to take the role. "More sensible people might have retired," the 83-year-old grinned.
National no doubt now heartily wishes he would.
Labour is hoping the use of Bolger to lead the process of bringing in the "fair pay" agreements will neutralise National's criticism and it is hoping so with some cause.
Fair Pay agreements will set minimum terms and conditions across entire occupations and industries.
National has depicted them as a return to the national awards system of the 1970s and 80s which were scrapped in 1987 after years of disruptive strikes and lock-outs.
Labour has sought to put the ghosts of those days to rest by rebranding them with the friendlier name of "fair pay agreements" and ruling out the ability for workers to take industrial action during negotiations.
There is some irony in Bolger's appointment. He was Prime Minister when National passed the Employment Contracts Act, legislation that effectively neutered the unions.
The appointment will certainly set business at some ease about the shape the fair pay agreements might take. Lees-Galloway has sought to ensure the process is constructive, saying he wants it to be an enduring model with wider political buy-in.
There is a way to go and once the recommendations emerge Labour could well discover that the appointment they thought was a coup was actually a Trojan Horse.
But Bolger was showing no sign of that. There was his Road to Damascus experience in his interview in RNZ's Ninth Floor series, in which he said he now believed the unions were not influential enough.
At today's press conference he said fair pay agreements were very much a thing of the future rather than the past. "We are not going to be looking backwards. We are going to be looking forward."
He spoke of doing something for "the almost forgotten" middle and adjusting the workforce to increasing automation.
"What about those who miss out?"
His only attempt to make good with the National Party he still claims loyalty to came in calling Finance Minister Grant Robertson "Grant Robinson" and warning Lees-Galloway about the size of the audiences at National leader Simon Bridges' public meetings.