That could have been the fate of all French connections if New Zealand's government had been a conventional partner in Western security. France was an obvious suspect since the protest boat was going to Mururoa, but it is one thing for journalism to leave a finger of suspicion pointing strongly at a culprit, another thing to know for sure.
If it seems improbable that a bomb detonated in downtown Auckland, killing a crewman, could have remained a matter of mystery and conjecture forever, consider the bomb that exploded in the Wellington Trades Hall the year before, killing a caretaker. We are none the wiser today about who did it and why than we were the day after the event.
I'm not suggesting the National Government of the day found out and kept it quiet, simply that crimes of that kind can remain a public mystery if a government considers it to be in the national interest.
Police quickly realised the Rainbow Warrior sabotage was not an act of some hotheads antagonistic to Greenpeace. As evidence came in it was passed to the Beehive where the head of the Prime Minister's Department, Gerald Hensley, convened meetings of the heads of Foreign Affairs, Defence, Police, the armed forces and the security agencies.
Hensley outlined the investigation in his memoir, Final Approaches, published in 2006. "At the end of a week it was clear we were looking at a professionally organised and well-funded operation," he wrote, "and with the help of some hints from a rival French intelligence agency with whom we had good relations we identified the prime suspect as the DGSE, the French external intelligence group, which had something of a cowboy reputation."
Hensley's book doesn't give any hint that they considered closing down the inquiry for the sake of relations with France and other Western powers, or to avoid the predictable embarrassment for New Zealand that eventually occurred. But it must have been considered.
While Lange was quietly encouraging us in the press to keep the focus on France, he was being more cautious in public. A week into the investigation he told a press conference: "There is absolutely nothing even remotely suggesting there is some form of government involvement in it."
A week later he added that in discounting involvement by other governments he included their intelligence agencies.
But at that point he also said: "From the best information, I have a knowledge of who did it and I know, from the best information I have, why it was done."
That was too much for the secretary of the Police Association, Bob Moodie, who called it "ego stuff" unhelpful to the police. Opposition leader Jim McLay weighed in, advising the Prime Minister to "shut up" in case he prejudiced a possible trial.
It sounded more like they had just realised discretion was not going to prevail.
The Government had barely completed a year in office. Its nuclear position had already offended Western allies. It was led by lawyers who were still learning that statecraft could not always rely on legal procedure.
The intelligence agencies that helped their New Zealand counterparts find out what happened would have expected it to be handled discreetly. Instead, the agents went to court, received an excessive sentence and France then made a fool of us.
Lange in his later years spoke and wrote ruefully about the experience. In his book My Life dictated not long before he died in 2005 he said, "Whenever I speak and ask for questions from the audience, the one I least want to answer, and the one I am almost always asked, is, 'Why did you give the agents back?'
"If it is put to me as an issue of principle, I can only acknowledge that it was not dealt with as such. If it was not an issue of principle I have to ask myself why I made it one, and I cannot answer that."
